Since bitcoin is very new and only the first generation is using it, so we do not come across such cases but after more than 10 to 20 years, a lot of bitcoins will be lost as the current holders of bitcoin wouldn't be alive and they have not transferred the wealth to their near and dear ones.
I don't know but I think with times to come this issue of people actually dying with their holding and Bitcoin will be reduced to a certain level because of the speculated amount of massive adoption and awareness that Bitcoin would have 10-20 years from now.
Bitcoin is something that is growing everyday and the awareness is also increasing and also is different technology and apps that's back it's usage and storage, although I not sure since it's a personal thought but I believe a time will come that a solution to this issue of people dying with holding will be of minimal number although currently now there is a fair share of people that have already called victim of this.
Since Bitcoin is all about privacy it will be wrong to give out your seed phrase to your family or even your spouse especially when you are holding and chasing a particular target but i feel if the person, that's your wife or child is already exposed to the technology then it will make the whole scene different because it will be easier to actually set some up some way for them to actually inherit your holding when you are no more .