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.