> But I don't see what other options are available for states to compete with each other if not through tax breaks.

Federal ban on tax breaks for companies over a certain market cap?

Why can't they compete on "we have a good regulatory setup" or "we have good schools for your employees" or "we are a nice place to live"? Why compete on "we'll soak or own taxpayers more than the next state over so you can make even more obscene profits"?