in comps, any method other than CFOP is extremely rare. If the same proportion of the community was focused on Roux, I'm sure we'd see some significant progress in the method.
I think this is a great point, in competition maybe 1/50 solvers use Roux (and that's optimistic, I doubt it's even that frequent, afaik no Australian cubers have used it in competitions just from personal experience).
Yet whilst there are so few Roux solvers, the 3rd fastest official solver uses Roux. If the amount of people using CFOP used Roux, there may be many more up there. One part of CFOP that's superior to Roux is how easy it is to learn and use CFOP at an adequate level. The Roux method isn't for everyone. It's also extremely hard to swap methods because CFOP->Roux often causes inefficient blocks due to so much practice to CFOP, and this just keeps more and more people into the CFOP method. Most YouTube videos that come up in searches are a few years old and teach CFOP. This is a barrier to Roux being used more.
When people make the switch from a beginners method to a speedsolving method, apart from the fact that CFOP is closer to the beginners method, people check what the world record holders use and copy that. When I went to my first cubing meetup I used the beginners method and the fastest people at the meetup, Feliks (11s~), Matt (13s~), Nick (16s~), used CFOP so I learnt CFOP in order to get faster.
All Roux needs is exposure, and gradually more people will use it, and eventually the methods will be more easily comparable.
One thing I like at the moment is that it isn't clear if either method is superior, so there's no mindless following, people have to choose.
When I started cubing, Feliks was the only colour neutral cuber I knew. He broke heaps of world records and now a lot of the people I knew have switched to CN, and newer cubers are just CN from the get go. If Alex Lau breaks a World record that stands for a decent amount of time, I would expect a huge influx of Roux users in the community.