The UEFA and domestic leagues does not have anything to threaten with.
What will PL be without the 6 big clubs? A glorified championship at best.
What would La Liga be without Real, Barca and Athletico. Not even better than the Portuguese league.
What would Serie A be without Milan, Inter and Juventus?
Banning players from Euros? Who is gonna watch second 11's compete in Euros?
They have no choice but to bend over.
Your nickname says all we need to know about your bias in this situation but let me try to 'discuss'.
First, the PL is not La Liga where people care only for the two big clubs with a sprinkling with Sevilla and Atletico (not
Athletico btw) Madrid (who both inevitably bottle the league to the former two in 9/10 cases).
The PL is built on equal distribution of money which allows for excitement in most games and unpredictability of the outcome each season(title, top 4, relegation). We have already seen that allowing Citeh to spend their way to a league title makes the league winner less unpredictable/exciting. Why should crap teams like Spuds and Arsenal get to benefit from big money when they've proven they're not good enough to compete with West Ham and Leicester?
Secondly, I would prefer to watch crappy little teams than these plastic big clubs owned by Yanks in a league facilitated by Yank banks (JP Morgan, please). Americans have proven time and again they have no understanding of European football in relation to its meaning to fans and communities, so I don't want them to have even an ounce more influence on European football.