And how can you trust the trust? We also have plenty of trusts which are questionably aligned with their makers last wills, among them the Nobel peace prize (Nobel didn't just want the prize to go to anyone working for any kind of advancement of peace. He had a very particular instrument for peace in mind, namely peace conferences, which I don't think any laureate has arranged for fifty years.)
I think we have too many trusts already. Let the living decide what's important in life, not the dead.
The fact that we are talking about bodies supposedly preserved in a state of suspended animation, not yet really dead, refutes your premise.
That's why I said "mitigate" rather than "completely solve." Incentives are aligned better with two entities who check each other and earn ongoing fees, instead of giving a lump sum to a single entity.
And the Nobels might not be awarded exactly as originally intended, but they are still awarded every year. Nobody has swiped the funds for executive bonuses, as the commenter above suggested.