The fewer bitcoins circulating in the world, the higher the demand for them and, accordingly, the higher the price.
Obviously, over time, bitcoins will become smaller due to the fact that people will lose access to their private wallets or, as you said, in the event of death.

However, most of the people will surely be safe for this case, especially exchanges that own a huge number of bitcoins.
The bitcoin deficit will increase in a natural way, which will make this asset especially desirable.