Trusts have always seemed to me to be pretty vulnerable. You have to trust the entire line of future trustees to actually implement what's written down in the agreement. Say I donate my property to a trust set up to keep that property a public park for 1000 years. I choose someone I trust to implement it when I'm dead. But, then that person has to choose someone they trust, and so on, and at some point in the future, inevitably it's going to fall into the hands of someone who would rather sell the land and spend the proceeds on hookers and blow.
It'd be nice to have a non-profit that honors these. Made of collective like-minded individuals. Protected by case law. You know, like a government is supposed to be.... But I suppose a big non-profit would work. Make one.
Everything is ultimately vulnerable, especially once you're gone. No institution lasts forever. Some are probably more likely to endure than others but there are no guarantees.