I estimate only around 19M coins will be accessible even when all coins have been mine. We can assume that the satoshi allocation is lost forever.
While these said bitcoins tagged as being lost/dormant for too long, some of them are just not being access by the owners still waiting for a time when they may decide to move it, we saw things like happened this year.
Also, some lost coins will also be found while a few will still lost theirs but as the value continue to increase the rate of losing bitcoins will be lower and the rate of even finding lost ones will increase well enough. It will become treasure hunt on the internet and the most valuable treasure will more likely be bitcoin.
Well I agree with you that the rate at which people will be losing their bitcoin will drop as the value of bitcoin continues to grow. People are becoming very careful, because any small mistake will make you lose big amount of money. Also you were right when you said some dormant wallets will become active as the value of bitcoin keep growing. But the one I don't think is possible is the one you said some lost bitcoins will be found. Like you and I know that any bitcoin that has declared lost can't be found. That's why bitcoin investors are always advise to be very careful with their transactions because any mistake can be very costly. Like the ones sent to wrong wallet that you and I know is lost forever, how do we find such bitcoins ever again? So I believe there will be no finding of any bitcoin that has been declared lost.