It is normal that some bitcoins will go out of the control of people or investors, many people die with bitcoins in e-wallet and those bitcoins cannot be recovered without that person, I think it is normal that those bitcoins are lost. The more bitcoins are spread among investors, the higher the price of bitcoins will increase. We want Bitcoin to spread to more investors and increase the amount of holders, so if Bitcoin is held like this now, then the price of Bitcoin will go up a lot later. It is best to keep our bitcoin wallet keys with own people so as not to get lost.
Reading this reply remembered me of something concerning those bitcoins that have lost due some circumstances like death or missing of security seed phrases. And phrases are not something you can just go pressing for forgotten phrase like how we do in password whenever we forget or misplaced it. If I may ask would it be a bad idea to tell few people you trust (like your relatives) your security phrase incase of such scenero because to me it would have been better for the family members to have the BTC that are being saved in the wallet than the bitcoin to lost and forgotten, Without no one knowing about it.
However, this will always be a possibility, we are human beings who are never free from mistakes and "forgetting" is one of the things in us that we cannot completely avoid because we are reasonable and sentient beings, therefore your statement and idea makes sense to me in the context of telling the password/phrase to one of the trusted people in our lives such as a wife or another family member.
It's like an inheritance, because after all all living beings will inevitably meet their end without being able to know in the slightest when, to be honest I myself do this, I rewrite the phrase on many papers and put it in many places in my house, and besides that I also tell my wife about this along with telling her how to cash it in. However, prevention is always better than cure, as you said that what is worried is that it is very possible that one day we can forget the passwords we have and another thing is that death will not be able to know when it comes, and by preventing this way at least our families can enjoy the results of the accumulation of bitcoins that we have struggled and defended during our lifetime.