Sure! Well, I can with the disclaimer that this is based on publicly available information. Exxon, and other large oil/chemical companies in the Baton Rouge area, also have plants in the greater Houston area. Many have facilities which are equal in size (plus/minus some change) to the Baton Rouge area operations, so you're looking at basically apples to apples comparisons. Today, even with favorable taxes in Louisiana, those companies (because it's not just ExxonMobil) choose to expand in those Texas plants instead. It could be any of the following things: natural resources, existing plants as feedstocks, pipeline capacity, port availability, knowing someone who knows someone (politics), physical space, and so on...

Now, I assume some of the choices are still influenced by the low costs of operating in Louisiana. But the surface level argument of "they'll invest elsewhere" is pretty ridiculous - they're already investing elsewhere.