Jon it’s devaluing the product.
The PL prides itself, or at least sells itself on being the best, most competitive league in the world. Having 3 whipping boys every year does no one any favours.
To level the playing field would involve a level of financial intervention & control that wouldn’t be tolerated by clubs, so the easiest thing is to control the quality and quantity of promoted teams.
I think the influx of American owners will increase the pressure on fewer relegation places, as it’s a model that they understand. They like certainty on their investment. Also from my limited understanding of franchise sports in the US (particularly MLS) they’re very criteria based. Quality of stadium, fan base, money to be spent etc.
If it can be argued that for the good of the overall product that promoted teams have to meet PL criteria, like in rugby union I think, I think that it’ll be brought in for all 3 promoted teams. “Do you promise to spend £x on new players?” “Does your stadium hold a minimum of x?”, etc. The governing bodies don’t appear to give out franchises Willy-nilly, and owners seem to move their clubs to other cities if they get a better offer.
If it’s not successful I think it’ll go to 2 promoted places, the second by play off. If it’s still a problem I can see it going down to a single place either by a play off in the champ or play off between the top champ side and bottom PL side.