In La Liga, the only competitors are Barcelona and Real Madrid . Every year someone from Real Madrid and Barcelona is crowned champion but the English Premier League is much more varied than La Liga. It is difficult to say when any team will be the champion here. However, Barcelona is not less than Real Madrid at this stage. Now Barcelona is a full strength team. However, Barcelona defeated Real Madrid in the last match and proved that Real Madrid is the best so far.
Indeed the rivalry for the title in the La Liga has mostly been between Real Madrid and Barcelona and that makes it less fun and less intensed and competitive unlike in the English Premier league where you have up to 5 teams every competing every season for the trophy and that is why the league is so competitive and interesting and it is difficult to say who will win from the beginning.
Yes, La Liga is already closely related to Madrid and Barca so that the public is often tired of watching the competition between the two. If it's not an El Clasico match, then don't expect there will be spectators outside Spain. Commercially, La Liga also felt the impact, so that La Liga became not so popular, then coupled with the departure of two Superstars Cristiano Ronaldo and Lionel Messi, it certainly had an impact on La Liga's rating.