who generated BTC? Of course btc miners, so how much they can generate depends on how much capital is invested. there are too many BTC generated by bitcoiner and some are missing so we do not know now how much BTC is left
It doesn't really matter...
The difficulty adjustment makes sure that
on average only one block is solved every 10 minutes.
The block reward is hardcoded, and halves every 210,000 blocks. The reward started at 50 BTC/block, but after 2 halvings, it's now 12,5 BTC/block.
Sure, a miner's bruto income will rise the more ASIC's he buys (unless the diff goes up more than can be covered by the additional hardware), but this doesn't matter in this case.
At this moment, on average, 12,5*6*24 BTC will be brought into circulation every day, by buying or selling of hardware, a miner can only influence how much of these BTC goes to him.
It does not matter if the miner that solved a certain block is known or not, it does not matter if private keys are lost, the bitcoins are brought into circulation, that's all that counts.
Only when a miner decides not to fund his mining address with the full block reward, bitcoin gets taken out of circulation.
If i were a miner, and i would generate blocks with a coinbase transaction funding my mining address with 12,499999999 BTC, my block could be valid for the network, but everytime i solved a block, i'd make sure that in the end (after the last halving), there would be one satoshi less in circulation.
