Most people who will be making substantial sums from an IPO, and therefore stand to gain substantially by minimising taxes, likely live comfortably in the area. They may have a strong community of friends and family here, well developed hobbies here, enjoy the benefits of living in California, etc.
Most people who will make that much money from an IPO likely want to be in a position to make new moves, take on new opportunities, and will want to be in the ecosystem where they can take on meaningful challenges. Establishing a new network in a new geography takes time, and there aren't that many great geographies to do so. Only a handful of states have no cap gains tax, so your options are pretty limited, though states like Texas or Washington could be good new starting places.