> why do we allow companies to do this? It should be trivial for the people of Kansas and Missouri to come together and say we won't allow a race to the bottom.

This is prisoner's dilemma 101.

Or, less cynically, cities compete in a free market where they try to compete for a limited amount of capital investment; there's nothing wrong with a city offering more attractive terms to be more business friendly, if they so wish.

Some cities can offer perks like an educated workforce, educational institutions of renown, nice weather, etc. to compensate for a heavier tax burden but everyone and every company has a breaking point after which they decide to pull up stakes.