Players often have 'highest paid player' clauses in contracts. It doesn't mean they have to be the highest paid player alone but that they will have parity with the one who is. So every Liverpool player with that clause (assuming there are some) will have to get the same salary. That leads to an explosion in wage costs eventually and is money they won't be spending on fees.
Same thing happened at united in 2010, when Rooney supposedly put a transfer request in. The whole affair was a charade to get the Glazers to double the wage ceiling, which is what happened. But not only did the 5 or 6 players with the relevant clause get an uplift, many others wer3 demanding a comparable percentage increase in their (lower) wages.