You have mentioned one of the Bitcoin biggest problems. We can't really distinguish bitcoins which own people who are already dead from the ones that are being held for the future. Satoshi case is a good example. We don't know if he is dead or not and nobody can't access his BTC. According to Bitcoin wiki, demurrage is one of the prohibited changes. Satoshi once said that all lost coins should be considered as a donation to the community because there will be fewer bitcoins available to buy.