How much Bitcoin is likely to become stranded in accounts because of users deaths? I imagine a lot, more than people have given it worthy of discussion. I bet a lot of holders if they got hit by a car and died would have no one to find their coins online...including their wives. Plus you got a lot of single guys using Bitcoin who aren't going to have a spouse to trust with their passwords etc even if they thought about it.
I would also add coins simply lost by people or forgotten. I personally have a bunch of tiny amounts of Sats in temporary addresses I made for different purposes, buy pennies and cents but they must add up. Add to that on purpose burning of coins and I wonder if we will even have any Bitcoin in 30 years.
the decimal point can be moved at any stage long before there are a shortage of coins
just because we divide a coin in 1.0000000 now doesnt mean it has to stay that way
could easily divide it into smaller units again