We have the richest clubs. And it's not just oil money, but Arsenal, United and Liverpool are rich and not bankrolled per se. We have more clubs in the top 20 global revenues than Spain and Italy.
We have the best viewer figures. Only the big Serie A games like Juve vs Inter (their Liverpool vs. Man U) or El Clasico in Spain can get good global ratings.
Our recent record in Euro competitions is good, compared to Spain and Italy.
And our league isn't boring, or corrupt and favours the big clubs in terms of viewership and TV rights/revenues (looking at you Spain..) La Liga was won by Atletico granted, but then this the first time in many years a non-Real Madrid/Barca team has won it. Most of the time it's just Real Madrid and Barca who compete.
And we're more tolerant/accepting than Spain and Italy...no black players here getting racially abused at their national training grounds. The Suarez/Terry things a few years ago were isolated incidents anyhow, hence why they get blown up a lot.