All forms of taxation and governance are subject to your same vague unfounded "concern" of 100%-embezzlement; the only thing about an estate tax that's special or different in that regard is that it mitigates the formation of a hereditary aristocracy.
A well-managed trust fund is, by definition, a conservative investment portfolio that only distributes a fraction of its value, and only to a chosen few heirs. A government spends its tax dollars, with a significant portion already going to welfare. Even the closest equivalent usage of tax dollars, sovereign wealth funds, are managed for distribution to the citizenry as a whole. Your premise is bunk.
A well-managed trust fund is, by definition, a conservative investment portfolio that only distributes a fraction of its value, and only to a chosen few heirs. A government spends its tax dollars, with a significant portion already going to welfare. Even the closest equivalent usage of tax dollars, sovereign wealth funds, are managed for distribution to the citizenry as a whole. Your premise is bunk.