we will not be able to foresee anything in this crypto market, it depends very much on the whales.

Well I think max supply of bitcoin reaching is not something we should care about because the closer we get the lower it would be to mine it and it would basically not be forever done. However lets assume that it is at a point where it is not making any money directly (for rewards) to the miner, do you really think that miners work for the reward only? They are also working for the fee and believe me the fee is a lot higher than it used to be thanks to (or because of) this halving, which shows that the lower reward gets the higher reward they will make. Obviously the fee could go down in bitcoin but still could worth a lot more in dollars when btc goes up, so as you can see they do have a plan on what to do when bitcoin rewards for mining doesn't make them any money at all.