I think in the future, cold storage will be seen the same way burying cash in a tin can looks today.
Today, managed wallets are risky, but they won't always be. Once Bitcoin managed wallets can get some form of insurance or at least a track record of reliability, I think the community will have a change of heart towards letting others guard their money. Maybe there's an economic or ideological argument against this, but people expect and demand that kind of oversight of their money.
I say either way, it's very irresponsible to not come up with a way to relay your savings to your dependents, no matter how young you are.
Edit: also, it's hubris to assume Bitcoin will be mankind's final currency. There are tons of currencies reduced to being collectable coins, and who's to say someone won't develop something better than Bitcoin that's incompatible with the existing blockchain?
I recall reading that scripting could be implemented into the btc protocol, so in theory future developments of Bitcoin could actually credit people coins if certain conditions were met. Perhaps it could require a digitally signed death certificate from a clerk or lawyer. Granted, that's a big undertaking and could be very exploitable if done wrong