No one can know what the future holds: the BTC mining difficulty, the various regulation changes in different countries, the capacity to produce ASICs of varying levels of performance, are absolutely unpredictable on a 5 or 10 years timescale.

Wouldn't it be too easy if we were able to predict the price of BTC and its difficulty? 


And even if they created a proof-of-stake fork of BTC, I don't know who would be crazy enough to turn away from BTC for a PoS-based fork.
As stompix said, it's been done before, and the result speaks for itself.

Wrong. After next halving BTC's block reward will be 6.25/2 = 3.125 BTC


You cannot predict difficulty adjustments, so it is pretty useless to try to calculate your futures potentials earnings with this timescale


Wish you it will be like that, but no one will never know about BTC's future price

S19 XP 141 

Current BTC mined per day  0.0003
https://www.coinwarz.com/mining/bitcoin/calculator?h=140.00&p=3010.00&pc=0.07&pf=0.00&d=52350439455487.00000000&r=6.25&er=1&btcer=30000&ha=TH&hc=5000.00&hs=0&hq=1

After Halving it drops to 0.00017
https://www.coinwarz.com/mining/bitcoin/calculator?h=140.00&p=3010.00&pc=0.07&pf=0.00&d=52350439455487.00000000&r=3.125&er=1&btcer=30000.00000000&ha=TH&hc=5000.00&hs=0&hq=1


 

1. Yes, each halving results in miner reward being cut in half.
2. No, it's impossible to calculate ROI (you mean ROI for mining right?). 
3. I guess it's possible if they will acquire at least 51% of all Bitcoin hashing power.

Not assumption because it is hard coded in the Bitcoin Protocol. Bitcoin block rewards will be halved after every 210,000 blocks.

Controlled Supply
How is the 21 Million Bitcoin Cap Defined and Enforced?

No estimation for ROI for miners because it will depend on their cost to mine bitcoins and price of Bitcoin at the same time.

Equivalent network time is interesting. It shows how many time miners will have to spend more to mine 1 bitcoin with time. It's not ROI estimation.

They can fork like hundreds of useless forks and many of them died.
How Many Bitcoin Forks Are There? You will be surprised!!!

It is per block not per amount as what others have explained, the reward block is the one that gets reduced.

Well, the thing on this one is that there's no accurate calculator depending on many factors if you happen to operate your own miner. Too many to consider just to get to the ROI. It sounds interesting when you see the calculation and projections on how quick the ROI and high the profit may be but all of those are just projections.

Just like with what Ver did and made his own bitcoin cash as a bitcoin fork and we've seen the bitcoin SV, so they're also able to do the fork but it won't directly have any code affection to the actual and real bitcoin. They'll just have their own version of Bitcoin as an altcoin but they can't change the real bitcoin's POW into POS.

You're forgetting difficulty will also go up if the price will do so, in your scenario when Bitcoin is at 400 000, the reward per th/s is 50 cents compared to 7 now and miners will not plug additional gear when an S19 is making 70$ a day burning 5$ of power?  

Use this:
https://insights.braiins.com/en/profitability-calculator
Play with both the price adjustment and the difficulty, throw in the fact that your gear might go boom, your energy price might go up twice and then you have a better picture of it!


Even if they have 99.9% of the hashrate it doesn't mean a thing, let's not even think of the other fact, they have 99.9% of the hashrate and they decide to make the coin go Pos? lol! No matter how much hash rate you have you will not be able to stop anyone to ignore and never stop using the old code!


No, it's not, that's not how a fork works.
They could do it without a single S1 mining and they could end with a dead coin like Bitcoin gold when if they had 99.00% of the hashing power.

That's right, the money miners get per transaction is divided by 2 after certain periods of time (or after certain number of blocks), so that mining power becomes less profitable, which can lead to leaps in BTC price during halving.

although the reward halves
what you also have to consider this the most economical efficient mining cost to mine less coins
because there is an ultimate bottom of planetary acquisition costs no one wants to sell below
which this month sits at $23k(its a number that sits below the markets but supports the markets above it)

now this is where alot of guess work comes into speculating the futures especially when trying to plan out the next 5-10 years

initially if we were to say all electric costskwh stayed the same for the next 10 years. hardware cost, hashrate all stayed the same
then the halving would mean 2x cost in 2024 and again in 2028
meaning if its currently $23k to mine the cheapest coin on the planet. it would be $46k in 2024 and $92k in 2028

however mining competition cost can change
imagine hardware and electric were same cost per kwh.. but the hashrate increased 2.6% per fortnight
meaning it would be 21 difficulty jumps of 2.6% or 65% in 300 days

would mean the day before the halving the min mining cost would be ~$38k which day of halving becomes $76k in 2024. yep $76k instead of $46k

now if you add in an inflationary 10% of electric cost which is about half of overall cost so a 5% overall increase. would be ~$40k just before halving which become $80k at the halving

so in a more hashrate increase scenario as just described. the baseline underlying value support can be anything from $46k-$80k just on these presumptions alone
where by the actual exchange market prices then peculate above that baseline

so have fun trying to look at all the variables.. and remember hashrate can go down too

of course.. next gen asics can come out that could do 2x more hashrate for same electric or less so those numbers can also be lower..

have fun speculating
or you can just quote the karate kid painting a fence 'upppp, dowwwn'