It's not a race to the bottom, it's an optimization. If corporate tax rate is X and total tax revenue is Y, past a certain point as X goes up, Y goes down because of competitive forces elsewhere.
Yeah, but if you give away more free stuff than you ever get back in revenue you will be losing money. This is what Ireland did. They got less than a thousand jobs out of it, and would lose them in an instant if they ever tried to make Apple or Google pay for what they actually use of public resources. Selling for less than cost is BAD BUSINESS.