i don't think so. specially since bitcoin is decentralized and nobody can have control over it because of that. specially if it becomes mass adopted and huge.

this part is true but it is because altcoins are designed that way. they were never created to compete with bitcoin but to fuel the pockets of those who own it. and on rare occasions when a coin is actually good i won't make it because the market is controlled by the pumped coins on top.

If bitcoin will hit mass adoption and by lightning network there will be solved scalibility issue I would love to leave from fiat to bitcoin with all my money and just use it. If more and more people will do that than bitcoin price will grow rapidly and other fiat currency value will be close to toilet paper. But will bitcoin become main currency of the world than? You need to remeber that oil/silver/gold/gas and manny others are valuated in dolars. And even if noone will use dolars in real life it will be still up to goverments to change pairs with oil and others. I dont think that US will agree to that cause it could totaly destroy their economy and value of dolar.

In a world we’re politics is controlling the financial system and reserve currency is doomed from its real purpose, but for power. Bitcoin won’t and will not be a currency for such corrupt and unworthy reason. That’s beyond said, any currency made to be on that position has been used badly. USD is in and won’t be replaced in a decade from now, but the possibility of change is big since China’s Yuan is competitive.

First of all Bitcoin is NOT a widely used cryptocurrency. Second, why would Bitcoin take USD place?
Bitcoin, as it behaves now it might become a store of value...digital gold as they say. But nothing is certain, people could easily migrate to another digital currency...which they have.

I think your highlighted statement here are wrong, And Bitcoin is a majority when it comes to mass adoption and we can say that it is the first and only Cryptocurrency that are widely use from different exchange sites, And online wallets, And among all Cryptocurrency they will sure need bitcoin as a base for other coins price,

And lastly taking into consideration that bitcoin can done anything, In my opinion Bitcoin can pose a treat to fiat currency that is why the government and some banks are against it, I really think there is a possibility they can do it, and replacing fiat money, I really think in the near future it can happen.

As the usage of cryptocurrencies is only increasing, the actual impact of the US Dollar tends to decrease, In case if the implementation of Cryptos will be successful, then this surely will loosen the influence of W Sanctions and the chance to sanction the SWIFT in particular. The use of Blockchain decreases the time and expenses of a single transaction, without the need of using 3rd parties. And as Bitcoin has spread worldwide, offering to substitute the adopted system of dollar, in my opinion, it’s just matter of time.

I  don't know if the bitcoin is become a reserve currency in the world because it is decentralized  cryptocurrency. A reserve currency is a large quantity of currency maintained by central banks and other major financial institutions to prepare for investments, transactions and international debt obligations, or to influence their domestic exchange rate. A large percentage of commodities, such as gold and oil, are priced in the reserve currency, causing other countries to hold this currency to pay for these goods.

Yes.The fact that it is a decentralized currency and cannot be controlled by the government will always remain.I'm sure the centralized government won't allow that to happen knowing they won't have the full control over bitcoin.But maybe accepting bitcoin and legalized it as a currency will somehow be possible in the next years.

It would totally defeat the purpose why bitcoin is made in the first place. Bitcoin is decentralized in nature and you're talking about centralization. This will never happen even in the future. Maybe there are other centralized crypto that can act as one but not bitcoin.

Professor of the University of South Carolina and consultant of Bank of Canada  Warren Weber last year published research that answers your question. Despite the fact that almost a year has passed, I think that this research is relevant, interesting and will be useful to many. There are only 30 pages, and it's worth your time. Highly recommend.
He compares the bitcoin to the gold standard. Two main similarities are the lack of control by the authorities and a limited amount of gold and bitcoins. The number of bitocoins is limited to 21 million "coins". "If bitkoyn becomes the world reserve currency, then on its basis central banks will be able to issue their fiat (not having their own value) money, thus, in essence, the gold standard that existed in the world financial system until the early 1970s will return."
In short, the essence of the research (and I fully agree with Professor Weber's conclusions) is that bitcoin could become a reserve currency, but it will not, because the principles of its creation and functioning have completely different goals.