I think what you are observing is for it to be more valuable to own any part of the Premier League. The top clubs were spoken for long ago in terms of ownership, so anyone looking for a piece of the pie needs to pick clubs lower down. When picking a club, you want one that has stability.
Eventually you get people having to invest in riskier clubs, like Leeds United, who don't quite have traction as they float in and out of the Premier League. This is still viewed as more valuable than other European leagues.
There are factors like ownership rules, limits on tickets prices, and politics in other leagues which make it less attractive for external entities to buy in. Therefore, there is less value in owning a smaller piece of it.
As with the Super League you'll get a lot of resistance from the clubs and authorities when there is a threat to some of the big clubs. They know that when things start changing, investment will come to some of the smaller and less successful clubs which will change the dynamics. Everyone knows that it'll change many elements of the game and people are rightly protective when they can be.