What Scarlet says makes sense. CEOs are looking for max profit, however, one does not necessarily makes the post profit on 0% tax, but in a well balanced nation (which could have a low tax rate but also decent welfare). In RL this is much the case, looking and EU which has very productivity, medium to low corporate taxes and very profitable corps.
In C3 nations GM might have to take a look at their default welfare levels if some balancing needs to be done, however;
To change the rules when the old business tactics cease to work is perhaps easy, but it dumb's both the game and the player down.
Adapt and prosper!
^^