* Apple, Google, Microsoft et al. have many foreign workers (green card, H-2B, or maybe L1 visa) and it is easier for american citizens to move/work outside of US than foreigners to get work visa in US. So the question is, if a country (like Spain or Greece) promises tax advantage for next 25 years and makes easier to get visa for employees, would these companies move their hq there?
* If, say, European Union provides better shield, would Apple move its HQ to Germany or Spain?
* Infrastructure: I can say most European counties have better infrastructure than US and it looks like most us companies build their own if needed. With $500 billion on hand, what would prevent these companies to build a better infrastructure in a host country.