Ireland and delaware are backdoors. they are not sustainable in the long run. I like to think of both as passing through an equalization phase.
Though, I think Delaware is past it. Even if they had higher corp taxes than ny, they would still win because of the "service" the judges provide by siding heavily with companies (over workers, consumers and even gov).
Curiously, Delaware also has no sales tax, in addition to attracting those corporate HQs, yet somehow manages to have excellent infrastructure, speaking for roads at least. Well planned, smooth, and bike lanes are widespread. If you cross over from Pennsylvania, the difference is immediately obvious: pothole city, narrow, and biking=death.
Though, I think Delaware is past it. Even if they had higher corp taxes than ny, they would still win because of the "service" the judges provide by siding heavily with companies (over workers, consumers and even gov).