There is the concept that dominant players/teams , "stars" so to speak, generate more interest in a sport. Tiger Woods golden years brought more interest to the golf, as did Arnold Palmer, etc. Tom Brady, as much as many dislike him, certainly hasn't "hurt" the NFL, and if he wins another SB, as much as many prefer he not win, doesn't make the NFL lose fans. Ditto Michael Jordan and his domination.
Dominant players bring discussion, media attention, etc. STARS do that.
Rafa's domination of Roland Garos is jaw dropping because it's carried across his best years AND Federer's best years AND Novak's best years. Look how many years he won RG when those guys were #1. That is a very unique distinction. A span of 15 years and counting: I don't think having no names win Roland Garos for 3-4 straight years is suddenly going to bring more fans/interest, but that's just me.