> Any discussion about tax reform has to start with government spending otherwise it's not serious.

I'd say almost the reverse. What we need most in terms of "tax reform" is to move away from thinking about taxes as solely a means of funding government operations, and towards thinking about taxes as a way of directly redistributing wealth. That is, the revenues of a wealth tax could simply be given to the non-wealthy as direct payments (possibly in the form of refundable tax credits). Unavoidably there will be some overhead, but there doesn't need to be anything for the money to be "spent on"; it can just be straight-up given to different people than those who paid it.