What if dedicated funding streams make people more willing to support a tax

You can have dedicated funding streams — they just have to be based on total revenue, not “the revenues we got from taxes that came from soda”. It would be insane to operate otherwise. After all, you don’t see someone at the store checkout line put back a dollar bill and say, “Oh sorry, that one’s from my side job… lemme find a dollar from my day job to cover this.” That doesn’t make sense.

How many more inefficiencies tend to get introduced to complex smart policies than simple dumb ones, and what are the economic costs of that?

I maintain my proposal is radically simpler. You don’t have to keep track of a list of inputs and outputs that are conceptually linked. You just put all revenues into the general fund, and you have a prioritized list of expenditures.