There is a difference between sugar daddies and a horde of fans, but at the end of the day the club with the huge advantage benefits the most from the advantage they have in revenue. Bayern has monopolized their league without a sugar daddy.
If it is true that most people only care about popular clubs being successful then you are right, neutering United and Liverpool will make people walk away
The German league is different to the EPL though. In the Bundesliga, Bayern acts like super massive black hole who sucks and destroys everything daring crossing its event horizon. Occasionally a German club might look as if its stole its shine for a while but in the end its destruction is imminent. According to Businessday 5 out of the 10 most supported clubs in the world are English (United at 3rd place, City at 6th, Chelsea at 7th, Liverpool at 8th and Arsenal are at 10th). Meanwhile there's clubs like Spurs whose fan base size is very close to that of Inter for example. To return to the astronomy analogy we're more like Jupiter ie a huge planet who plays an important role in the solar system (ie it attracts most asteroids to itself) but isn't big enough to dominate all other planets.
Ok I've been fixating on astronomy at the moment so apologies. My point is that United could never become Bayern. Even in our prime (ie lack of powerful sugar daddies or state owned clubs)
A- United couldn't just knock at the door and hoover the best talent out of every single club. Shearer, Gazza and Anderton were among the players who got away. Meanwhile hell would freeze before we could get our hands on the likes of Henry, prime Michael Owen, Steve G, Vieira etc.
B- Even in our prime the league was extremely competitive. During the treble season we garnered just 79 points (ie the amount of points City having played just 34 games), we won the league with just 1 point and we drew 13 out of 38 games
C- From 1991-92 till 2001-2002 we were only the biggest spenders twice (1998-1999, 2001-2002). Newcastle were the biggest spenders 3 years in a row and Blackburn 2 years in a row, with Liverpool, Everton and Leeds being the biggest spenders for the rest.
Revenue by itself won't create monopolies in the EPL. That's because other clubs have fan bases that are big enough to still go toe to toe with us. What these rules will do is rendering the hard work generated by clubs to build their fan base up fruitless while removing the occasional big spend of clubs that might make them competitive. In that case they would either not invest too much on such effort or they'll find alternative routes to capitalize from such fan bases (Super league?). Guess who benefit of such huge fan bases? The answer is the smaller clubs, cause subscriptions is what persuade companies such as SKY to throw money at the league.
Then there's the non footballing factor that comes to play ie tourism. In 2017 Manchester welcomed 2.4m domestic visitors and 1.32m international visitors. The latter in particular would need hotels, taxis and will eat out. Ask yourself why the vast majority of those 1.32m visitors go to Manchester rather then London, Paris, Florence, Rome or Madrid. :Spoiler alert: Its not for the Trafford center