I am lucky enough to have a FLGS that encourages other RPGs. I am currently running Dungeon Crawl Classics, and we have a GM running Degenesis: Rebirth, and another running Numenera. Prior to COVID we had a pretty active D&D group going (running games every night of the week, and multiple games on Saturdays and Sundays). I was one that was desperately wanting to get a group into tabletop RPG games. I started a FB group and had some business cards made advertising "Play D&D". We grew from 3 members to 130 in four years, and most only want to play D&D. Even the store says they have people asking to learn D&D. The pop-culture today has made "D&D" the term for roleplaying games, much like "Xerox" was standard for copy machines, or "Hoover" was synonymous with vacuum cleaners. Some people asking stores if they have any D&D going on, may not even really know what D&D is.
It's kind of deceptive, but sometimes, instead of advertising DCC, Deadlands, etc. I just tell people I'm running a "Western-themed D&D" or a "Space-themed D&D" (for the Firefly RPG). I find that people may be drawn by a theme/setting rather than the actual game itself.
I am planning on running Bedlam Hall (PbtA), One Ring 2e, and Alien RPG in the near future as well. So far, I have at least some interest in all of them! People in our group are starting to branch out, but it is a long-drawn-out process, but there is now a growing interest in systems other than D&D.
Heck, I had a full table for the Wendy's RPG! Yeah, I ran it, and I'm not ashamed! lol!