Question... How much money do you think the one that owns these have;
Let's do some basic math... You want a crypto mining billionaire. Ok. So, right now, let's use Bitcoin as a reference. Let's say Bitcoin is $60k USD. In order to be a billionaire, the miner needs to have 17k Bitcoins, rounded up.
Next... Around 900 BTC are created per day. Assuming the largest miner has about 3% of the total hashrate, that would mean they would get around 27 BTC per day. That's about 9500 BTC per year. That would mean that in less than two years, one would be a billionaire, if there were no expenses. Obviously those are there... But... Considering the amount of time we are talking about here... I don't think it's impossible to become a billionaire through mining, if you already started a while back...
Also, take a look at the addresses with the most Bitcoin... How many Billionaires are there...? Obviously we don't know if they mined them or not, but it would be hard to believe that there are no miners among all those;