The time it takes to mine 1 Bitcoin depends on The hashrate (speed of your mining hardware).
The most performance machine these days is Antminer S19 100TH Or any other brand with 100TH hashing rates.
To calculate right, you have to focus only on hashrate, don’t consider any other factors like electricity rate or bitcoin price.
100TH hashrate produces 0.00035 of bitcoin daily. So we can calculate 360 days of reward = 360 x 0.00035 = 0.126 BTC per year. and if we consider only a 5% increase in difficulty per year ( This is the average difficulty rate ) we will get about 0.125 BTC yearly. Yes, it’s about 7 years to mine 1 BTC using Only 1 Machine 100TH speed. Now you can calculate How 8 miners can do in Only 1 year.
How long does it take to mine 1 bitcoin ?
After this calculation, The answer is 1 Year using 8 Miners.
Let’s talk about business and profits.
One machine 100TH cost now about 1500$, 8 Machines cost 12,000$ + 14000$( Hosting fees or Electricity fees) = 26,000$
So, You Invest 26,000$ and you will get 1 BTC at end of year.
The question is ” How long will an Antminer S19 last? “
It’s run 24/7 for 3 years.
You have to sell your mining reward only in the bull market when BTC price reaches again 50-70k$ .
Happy Mining For All.