You have it all backwards. Star Wars is now just another franchise whereas it used to be the biggest franchise. But whatever, everyone can see what you've written and I doubt you're going to get anyone agreeing. It's just common sense.
I'm so late on this, but nah, yo. TheHunter is correct that Star Wars simply has more competition since these kind of popcorn blockbusters weren't as prevalent before Star Wars was a thing.
Star Wars twice was the highest grossing movie of the year this decade, with Force Awakens smashing an opening weekend record and easily becoming the highest-grossing movie domestically of all-time. Two of them were billion-dollar movies, and adjusting for inflation doesn't really work because how we consume movies is completely different. Back in the day, watching movies at home wasn't as big. Movies didn't release on home video a few months after a theatrical release; you had to continue to watch it in theaters and wait for re-releases. You didn't have a ton of channels in 1977 on cable syndicating movies to watch at home as we do now where tons of movies can be watched at any time on cable/satellite. You didn't have all these streaming sites and Redbox rentals and ability to purchase movies on Playstation/Xbox/Amazon/iTunes/etc. Which makes Force Awakens even more impressive because it grossed more than Empire and RotJ even when adjusted to inflation, and Last Jedi outgrossing pre-Disney prequels, save for Phantom Menace, which was an event movie similar to Force Awakens.
But all that aside, you're talking about movies that are able to be the #1 movie of the year while still making bank on home video (Last Jedi was the best-selling Blu-Ray of 2018, and Force Awakens the best-selling Blu-Ray of its year), downloads, streaming, and syndication, never mind merchandising.
It's easy to be the biggest franchise head over heels when you're not competing with as many of these blockbuster films. There's no Jurassic Park, no MCU with events movies ranging from a culmination in Endgame to an event like Black Panther, there's no record-breaking Batman films or Dark Knight trilogy, there's no Pirates of the Caribbean (which we forget was a monster in 06), no Spider-Man trilogy, no Toy Story, no Shrek, no Hunger Games, no Twilight, no Lord of the Rings, no Avatar, no Lion King, no Finding Nemo, no nothing. Those movies weren't there. Now they are, so Star Wars isn't the only cool kid on the block, and it's still a powerhouse.
Perhaps RoS should have been a better movie with better word-of-mouth. It'll be the odd one out in a series of bank-busting, critically acclaimed movies that made money hand over fist, and it'll still rake in dough.