Pay it to whom, though? Ireland? The US? Does the country with the highest tax rate get to set the global corporate tax rate?

I don't think any developing economy could possibly agree to such a scheme - it eliminates a less-developed economy's ability to compete for investment against established incumbents by offering tax incentives - I think this ends up translating to unacceptable protectionism for any non-economically-dominant country looking to attract investment and compete in the global marketplace. There'd never be a 'Celtic Tiger' economy under such a scheme.

US States, incidentally, compete for business on a similar basis.