> It is perfectly legitimate for a company to be incorporated in Delaware and to register as a foreign corporation in other states where it has a presence/does business. You can pick any random Fortune 500 company and look up its registrations in the states where it does business.
It may be legal, but it's rather more questionable if it's legitimate: the latter is a value statement in casual language, even if legal jargon would be more precise.
If I do business with people in all states of the USA*, there should not be any particular state which attracts a majority of big (and everything bigger than "small") business registrations: other than network effects (e.g. everyone else does it so the corporate lawyers are all right there), anything pushing so many businesses to choose one specific state, be that for taxation or for a court system that presumes more in favour of businesses than elsewhere, this creates an uneven playing field for other states and who gets what powers of enforcement for business (/consumer) laws they pass.
Like, people here argue the EU is "anti-business": well, the American-registered factories (Tesla) and American-owned IT company offices (Apple, Microsoft, Google, etc.) are still here, and the shares are publicly traded so even us Europeans can own them, but they count as "American" because of where they (/their parent companies) are registered. Even Google Deep Mind (HQ: London) gets called "American" due to the ownership structure.
* A similar argument applies to the EU
I don't have time to go into a long-winded explanation of why so many corporations are set up in Delaware (there's plenty of information online about this) but I want to address this point:
> this creates an uneven playing field for other states and who gets what powers of enforcement for business (/consumer) laws they pass.
Setting up your company in Delaware does not mean that you are exempt from the business and consumer protection laws in other states.
If you're a Delaware company and you violate consumer protection laws in California, violate environmental protection laws in Colorado, defraud investors in Maryland, etc., the relevant authorities/powers in those states will all be able to exercise jurisdiction over you.
Being incorporated in Delaware does not mean you have free reign to do whatever you want in any other state and have disputes over your actions adjudicated in Delaware.