if that would make money, they'd have done it years ago
the challange with that arguement is it would make money & I think its more a question of timing.
With the exception of the PL, the "big clubs" in all other leagues have the TV deals stacked in their favour. Barca & Real have over 50% of the revenue from driving well over 50% of the global viewing, which while on one hand sounds fair enough, it creates an uncompetitive environment, which ultimately is costing them longer term with TV money decreasing and they are suddenly exposed and seeking further revenue. Similar stories in Italy (Juve get almost 20%) & Germany, where the traditional power houses, get what many would argue is their fair share of the pie.
So why now...
No need to be a genius to see how hard Covid has hit across Europe. The threat of a Superleague is probably more live now than ever before & as so, the PL team feel they have the leverage to negotiate hard with the other clubs & the league themselves. For the sake of balanced debate here, I am going to drop both merseyside clubs from the example below.
Man United in 2013 delivered 52% of all viewers in the PL globally, they are still delivering over 25% and yet they recieved just under 7% of the TV revenue last season. Being honest, if I was in there shoes I think I would be asking the same.
What will happen....
there will be more kiting of a European Superleague; followed by PL debate and some of these concessions met and a middle ground around "revenue share" & voting rights, which will increase "big club" revenue making it harder and harder for the likes of a Burnley / Sheff United / Brighton etc. We will probably benefit; but not to the same level as the traditionally top teams