Barsa and Madrid should see that it is in their interests to enable the lower level clubs to have larger earnings in order to make the league more competitive.
This is just a general problem in football. Most European leagues are completely uncompetitive now. PSG should walk the French league (when they didn't it was won by another oligarch-owned club), Bayern have won the Bundesliga every season since BT acquired the rights, ditto Juventus, who have won the last 7 Serie A titles, 4 consecutive trebles, and 18 of the last 21 Italian trophies.
Spain is more competitive than most because at least there are two big rivals and a third credible club. Usually three competitive clubs is the limit (and increasingly there are less than three). England is a unique case because for two reasons. Firstly, having the 92 league clubs means that there is a supporting culture all over the country, and this has resulted in lots of big clubs. Secondly, London is such a massive city that it can support three elite clubs, plus West Ham who are one of the biggest outside the top six. With Palace and Fulham also being in the top flight, nearly one-third of the clubs this season are based in London.
You don't get this in other major cities based in other European nations, there aren't six credible clubs in Munich or Milan or Madrid. London is generally a massive leach and drain on the entire country, but its sheer size and economic prominence does, arguably, have a positive impact on the PL.