Checking the money league 2025, Dortmund had the 11th highest revenue and Atletico are 12th so the best of the rest in Europe financially. Look at the commercial as this is what I meant about the global pull of the big 6 compared to the mags. It's all the eyes around the world on those 6 teams that demand big money from sponsors/ads etc along with merchandise and all other revenue streams etc. Football has grown massively globally since the Man City takeover, especially on social media in recent times. It's part of the reason why the PL International TV rights are now worth more than the Domestic.
Bear in mind that some of the commercial for the mags is inflated due to Saudis self sponsoring more than they'd get from a 3rd party and nowhere near the lowest of the big 6 pull in, which was Arsenal with €250m. The mags will never get anywhere near that winning a League Cup, or even FA Cup. They'd have to be winning the PL or CL a lot more consistently or being contenders season upon season for many seasons to even build up a global 'fan' base that will follow them when they don't win anything.
That's also ignoring the issue of location for the mags which means higher wages given there's not as much concentrated wealth up here (footballers/actors/musicians/millionaires etc) to mingle with, or the same amount of places that cater for that kind of wealth.
Long story short, the mags certainly ain't gonna be another Man City and won't even be part of the elite anyway even if they build their shiny new stadium as having a big stadium doesn't win things, just ask Spurs. As some have said, it's a closed shop at the top of the PL and any team trying to get a place at the table may get some scraps in a doggy bag but they'll never get a full plate to munch on. If they try too hard and it all goes wrong then see Leicester as to what could happen.