Interesting comparative chart!
PL and La Liga also enjoy a wider world wide TV transmission hence the vast fan base for the clubs in these 2 leagues.
Also, apart from Barcelona & Real Madrid, there is steep drop in other La Liga Clubs. It will be interesting to see the impact of Messi’s presence in the League - I am sure a matter of great concern for the League management anticipating Messi’s exit / retirement from the league in the near future.
PSG’s attempt to acquire star power doesn’t seem to have any advantage here.
I guess as long as 2/3 clubs secure the top 4 spots in the 4 leagues it will be difficult to match or even come close to PL fierce fandom and rivalry.