This is a common question posed by the strange opponents to promotion/relegation in the U.S.
I say ‘strange’ because I find it a bit strange at how concerned these folks are with billionaires’ investments, while nobody has asked the billionaires what they think. Many of these billionaires have invested in clubs that are in promotion/relegation systems. So, it seems by their own actions, the fear of being relegated isn’t a big concern.
But, also, the folks who don’t want to replicate the structure of soccer in other countries seem fine with copying other things, like their team name conventions (e.g. [City Name] FC or [City Name] United) and uniforms.
Why be against copying the structure of soccer and not be against copying these aspects?