Yes, but that is a tax somewhere else. If we decided to tax financial services, who would decide how to spend the money? It is a whole other decision as to whether to spend it in the pension system or somewhere else.
Personally, I think the expenses should be tied to the benefits. As for insurance, who will pay for insurance on those benefits? Most of the time, the problem is that the companies that fail have not paid their share. So I do not know how they would be able to pay insurance premiums. That is what I am wondering.