The difference is the likes of Bayern, Real & Barcelona don't want to have to spend this amount. They want to be able to cherry pick the best players from their leagues at the minimum cost possible.
Bayern for example want to be able to sign the best Bundesliga players, whilst paying the smallest possible fee's. In fact I'd go one step further and say Bayern want to get players to run down their contract to sign them on a free. They would have been incredibly irritated by City snatching De Bruyne, Sane & Gundogan; as historically they'd have probably gotten all three for a minimal fee. Likewise their reported interest in Sanchez was curbed the second they heard of his salary demands which could have been met by multiple PL clubs. Barcelona likewise are naturally furious that PSG were able to trigger Neymar's release clause, but also that Liverpool could hold out for £140m, rather than the much smaller £65m they were able to sign Suarez for. They tried all the tricks in the book with transfer requests and even pushed him to go on strike... But the net result was having to write a £140m cheque. I'm sure Real Madrid are likewise getting nervous about the quoted costs to replace Ronaldo/Benzema/Bale - the £200m fee for these three combined players is likely to not even be enough to sign one forward like Harry Kane.
Bayern, Madrid & Barcelona are likely to always have a higher revenue than Liverpool. However when Liverpool can offer a larger transfer fee than any of those three (and indeed anyone full stop) have ever spent on a central defender, along with a weekly salary comparable to any defender in the world, it decreases the amount leverage that those three clubs have historically had. If Hummels had 2 years left on his contract in the current climate - The likes of United, City, Liverpool, Chelsea and Arsenal would have the funds to offer them £75m, meaning Bayern would either have to pay up or step back, as they did with De Bruyne, Sane etc. Likewise if Suarez were now leaving Liverpool - Barcelona would have to pay a Coutinho type fee as they'd know there would be 3-4 other clubs willing to spend a nine figure sum on him (unlike the other offer at the time - Arsenal £40,000,001)
The fact that United, City, Chelsea, Arsenal, Spurs & Liverpool all have a transfer record that is now higher than Bayern's illustrates why they're pushing for change.