In case of death, I think we have our own plans of how we will introduce our private keys to our parents, children or immediate relatives.
You are right! I bet most BTC hodlers have a plan on how to convey their digital assets to their intended beneficiaries when the time comes. As a matter of fact, there are services and mechanisms that caters to these kinds of needs from these hodlers and at the same time, other digital assets have also plans to set up infrastructures to mitigate these kind of situation.
I did found an article that could enlighten us more about this matter.
https://www.coindesk.com/bitcoin-firms-report-uptick-in-demand-for-inheritance-servicesSo in essence, I disagree with OP's idea of BTC being crushed in the future on the premise of mishandled private keys alone. Imho.