The Premier League hold the most important ticket in town here, I still think they hold the power, ESL loses all of it's value if the 6 English teams aren't there. Only so many El Clasico's in a row people are willing to watch.
The ESL want's to run alongside domestic competition, the Premier League can stop that. American investors are backing this because the English sides are there. The Premier League has to kick them out, take the financial hit and hope they come crawling back.