I’m not so sure. A major part of why the NFL works is it’s competitiveness and ‘level’ playing field (which can be debated), Without getting in to huge detail a big reason it can do this is because of its draft structure, which is fed by the college and high school sports systems which just cannot be replicated. The model cannot get close I don’t think.
An entire state can support an NFL team too. 32 teams across a population of 300 plus million across North America. You might have a similar population across Europe, but you’ve hundreds of sides with history and loyalties. Most fans aren’t going to suddenly start supporting one of their countries representatives. You alienate a lot of your market.
The corporates would love it, I’m not sure fans would ever get on board.
Yes there are differences but if there was a closed European super League there would need to be similar checks and balances to ensure a level playing field otherwise it could go stale very quickly.
Fans are interesting and I would divide them into broad two groups. The committed match attending fan and the rest. The former is very much the tip of the iceberg whereas the vast bulk of the target group for this league or any other is the none committed casual fan who will watch it on TV. Millions will watch a game only tens of thousands will attend a game.
Obviously the league can count on the fanbases of the clubs involved and given those teams are generally the best supported teams in their countries they won't be playing in front of empty stands.
While most of the fans I know would hate the idea many wouldn't watch it but then again most of them are like me committed fans but they aren't typical.
My brother in law bless him is far more typical. A nominal Man U fan he has been to a handful of United games and is so uncommitted I can't even be bothered to taunt him on the occasions the Albion have beaten his boys, mainly because I forget he is one. His viewing habits are revealing he is drawn to the big occasion even if it doesn't involve his team. He will watch El Classico but would never watch Getafe v Eibar. He absolutely roots for English clubs in Europe competition and worse still is likely to buy Amstel beer because it's advertised during the transmission. He is far more typical and he would absolutely lap up a European Super League.