I think you are wrong if you say other teams don't have good strikers or strikers who are hungry for goals. Celta Vigo has Iago Aspas who is very diligent in breaking into the opponent's goal, Raul de Tomas who plays for Espanyol is also very dangerous, these two players are below Benzema in the list of top scorers in La Liga last season. Enes Unal (Getafe) and Juanmi (Real Betis) each scored 16 goals last season, while Deportivo Alaves (Joselu) froze 14 goals.
The reason Real Madrid, Barcelona and Atletico Madrid dominate La Liga is not because other teams don't have good strikers, but because the quality of players that these three clubs have is above average when compared to other teams.
Good, you have explained it quite clearly. So it's true that the quality of the team between Real Madrid and Barcelona compared to other teams will definitely be very different. You can also look at the total market value between these teams as a good comparison to assess the strength of the club, financially as well as quality.The reason Real Madrid, Barcelona and Atletico Madrid dominate La Liga is not because other teams don't have good strikers, but because the quality of players that these three clubs have is above average when compared to other teams.
Here are just a few teams that have a total market value of over €100M, and the rest below. Source: https://www.transfermarkt.com/laliga/startseite/wettbewerb/ES1
