Bitcoin has been more and more centralized for a long time. I’ve seen some signs of decentralizing mining lately though. The increase of popularity in lottery mining is a great thing to combat big mining companies that are centralizing hashrate. At some point the market will correct and lottery miners that don’t care about profitability are going to add salt to the wound of debt ridden mining companies struggling to maintain their business during a time of no profitability.

The Bitcoin blockchain is not centralized, and no organization is controlling it. It is completely decentralized. But yes, Bitcoin price movements can light up the market due to some large institutional investors buying huge amounts of Bitcoin. But this does not mean that Bitcoin will lose its decentralization or independence.
    Bitcoin uses a Proof of Work (PoW) algorithm, so no one has any control over it. If only censorship is introduced and enforced, Bitcoin will lose its decentralization and become centralized, but that would completely work against the purpose of Bitcoin.

Has Bitcoin Finally Lost Its Decentralization? The Answer is no I mean if you talk about bitcoin circulation the company like Blackrock own fraction of bitcoin supply tho in theory Blackrock can bought all the bitcoin with their AUM hahah that right now counting 3 Trillion dollar but hey is not easy like that. Some country like Elsalvador start accept bitcoin as a payment but this alone not gonna make bitcoin lose its decentralization/

Bitcoin mining in other hand looks like own by big company like DCG group that own now 30% of Bitcoin hashrate but somehow the community still here and make 51% attack impposiblle at least for now.

We are hearing this question since many years in my opinion it would not be centralised as we don’t know who is controling bitcoin right now. There is no company or individual who claimed to control bitcoin’s price. If bitcoin is or was centralised then the price may be fixed at some point but we see dips and pumps in bitcoin’s price and by time passing the bitcoin grows as members added to this community and people prefer bitcoin just for it’s decentralisation.

It isn't even about an individual or institution claiming control over BTC, the network was designed to be decentralized and censorship resistant, it is not possible for it to be centralized because there is no single point of failure. The government cannot seize the network, unlike how they do with mixers and centralized services, there is nothing to be seized in the BTC network, nodes are scattered all around the world, so there can be no central authority over the BTC network.

I feel like people are talking past each other here. People have different definitions of the same term and are answering it accordingly.

Is Bitcoin "decentralized"? It depends on what you mean by "decentralized".

The term can mean:

1. The data for the ledger is stored in a highly redundant way, making it essentially impossible to lose a transaction.

2. The systems holding the ledger can be governed by multiple separate legal entities, making it difficult for governments to exercise any control over the software.

3. The way most people use the product is self-custodial, such that they are actually effected by #1 and/or #2.

Hence:

1. Systems (whether they use the blockchain architecture or not) that store the ledger on an insufficiently geographically disperse datastore are "not decentralized". In this sense, Bitcoin is very much decentralized.

2. Currencies that are on networks controlled by a single legal entity, or a small and identifiable number of entities that could easily be captured by a government (viz. all PoS networks like Ether) are "not decentralized". In this sense, Bitcoin is mostly decentralized (although >50% of the hashrate is controlled by only a few companies).

3. "Not your keys, not your coins". Unless you physically hold your private keys on your actual person using your own private storage system (e.g. your iPhone) then you are not using a decentralized product by any definition. Most people today use Bitcoin and other cryptos through a broker or an app that either stores their keys for them, or simply marks their holdings in some central database. In this sense, Bitcoin is not, in the defacto way people use Bitcoin, "decentralized".

I think those saying "Bitcoin is not decentralized" are saying it in the sense of #3.

I think those saying, "only Bitcoin is decentralized and all other digital currencies are not" are saying it in the sense of #2.

I think those saying that most of the more popular digital currencies like Ether etc. are still "decentralized" are saying it in the sense of #1.

Personally, my own focus is average consumers and getting digital currencies to be a mainstream mass-appeal phenomenon. Hence my own viewpoint is that of #3 when you ask me this question. My answer to the survey above was, "who cares?" (yes, that was me ), and I answered that way because the customers I focus on definitely don't care, and the market is showing us that at least 90% of the market doesn't care.

I think a lot of the people who answered "no" are, like me, thinking in terms of #3.

People who answered yes are thinking in terms of #1 or #2.

If I am not wrong, this matter has been discussed many times. You may use the search button to get old discussions and more ideas. Technically, Bitcoin will remain decentralised always. Since wallet doesn't have limits, anyone can buy any amount, and they can sell as well. There is no way to prevent them, and that's why Bitcoin decentralised. No one can control it, either trade, buy, or sell. When someone is selling, on the other hand, someone is buying too. It does lead to a drop in price, though it doesn't make Bitcoin centralised anyway. The function of Bitcoin is decentralised; this wouldn't be questionable. 

Bitcoin network remains decentralized, and it will stay like that with proof-of-work, but distribution of coins is changing after Blackrock entered the market and start buying coins.
This is not the only company who decided to invest in Bitcoin, but they have most power to manipulate markets because they are majority owners of most assets in the world.
Everyone can help Bitcoin decentralization by running their own nodes, using non-custodial wallets, and decentralized exchanges.

I have always attributed Bitcoin decentralization to it's network, and other criteria comes second. As long as no individual is in charge, then it's still holds its quality of decentralization, and not necessarily centralization. But taking a look at how it's currency is been distributed among hodlers, which is enough to question the decentralization since certain users have more portion of it than others as a result of differences in purchasing power. But I don't really see any threat in this, as long as the individuals who buy Bitcoin massively are not a single entity (i.e they don't work for one another).

The most important factor that keeps Bitcoin decentralized has been how the network is structured, where everyone depends on another to make changes (i.e take a decision). No single person can just wake up and make some changes without the consent of thousands/millions of users that are connected to the same network. So, I still believe that Bitcoin is still decentralized, and will continue to be decentralized, as long as it is not managed by a single person.

This is probably what @mrquackquack meant when he spoke about the decentralization of bitcoin (although this is not entirely correct), when large holders of bitcoin can influence the price and manipulate the market.

If this becomes known to the BTC-community, and before that moment there is time to do harm.

How many active BTC-developers are there at the moment? Probably a few dozen at most?

There is another point regarding decentralization: the majority of the hashrate (computing power) is in the hands of only a few mining companies, which also doesn't benefit the discussions about decentralization.