Who said anything about internet stores being required to support all locations? Nothing is stopping an e-commerce outfit from restricting sales to a particular state, or county, or city, and simplifying their tax situation considerably. And brick-and-mortar chains with multiple locations already have to deal with these rules.
I don't see the "huge disadvantage" you're talking about.
Engineers are clever. Sure that might be true, but now that cleverness is going to be wasted building tax compliance solutions which aren’t even close to being “not much of a burden.”
The smallest possible correct program implementing a tax calculator is going to be a LOT bigger than the smallest possible correct program for controlling a 60's era manned flight to the moon. The latter is more complex in other ways, of course.
Complexity can be "deep" or "wide". software for rockets is "deep and thin complexity", but calculating hyper-local minimal tax bills is extreme "wide and shallow complexity".
Orrrrr a couple of companies will step into this problem space, solve it, and everyone will offload their tax compliance to those companies, in exactly the same way that we don't all waste 1,000,000 engineering hours on the arcana of banking and credit card networks and just offload that concern to payment gateways with nice APIs.
This is already the way it works in most of the world. HN is showing its provincialism by convincing themselves this is some kind of impossible-to-solve problem.