All bitcoins that are not moved for a certain period of time (20, 50, or 100 years) should be presumed lost and then recycled through the usual mining process. I'm not sure if that can be achieved through a soft fork.
If something like that occurs, the whole idea of BTC will be lost
You can hold BTC for years and years and never move any satoshi, and you'll have access to the coins you have
Some move to recycle BTC can create a breach
Satoshi itself said (like LoyceV pointed above) the lost coins can be a donation to BTC
Knowing human nature by 2075 the move them or lose them movement will be strong 💪 and they will begin to move frozen coins. So any 2009 still in place will have a time period to shift them or lose them.
So a 50 coin address simply need to pull .00000001 to a new address and problem is solved as it prove the coins are not abandoned.
Satoshi mentions lost coins but not abandoned. The powers to be will say those are abandoned and will take them..
To those that think it is wrong or bad or terrible oh well I don’t worry as I figure I will be dead around 2047 if lucky maybe 2057.