Wolfpack48
Hero
The only thing I can point to is my own experience. I started roleplaying in 1976, with of course Basic D&D. We moved on to AD&D pretty quickly and played it for years, had a lot of fun. But throughout that time we were trying different games, Call of Cthulhu 1e, Paranoia, RuneQuest, Champions, MERP, Rolemaster, Traveller, Harn, Star Wars, Top Secret. All that time D&D was the dominant game most people played. At no time did we feel hindered from trying other stuff. Maybe today there’s less 3rd party content on the shelf at the local FLGS, but I still do find other titles. And of course Drivethru. For our last RQ campaign I advertised it specifically (bulletin board at the game store) and got a decent number of responses, 2 new people who joined a 2 year campaign who we still play with. Maybe it’s more selling the campaign idea over the system that pulls in new players but I’ve never got a “I only play D&D” response.