It’s like any of the other sub genres, they often start off in just a club or two with a small crowd that are into it that eventually generates enough buzz that it mushrooms in popularity. I remember listening to people like Jason Kaye, Mikee B , Timmi Magic etc when it was a really niche sound but within the space of a few years it just turned into a commercial sound and scene that attracted bellends to clubs that were all about wearing designer labels, Bronson and swigging Kristal.
Garage/Speed Garage/2-Step or whatever you want to call it was really at the right place at the right time. It benefited from the peak of house music, was popularised on the house scene by people like Armand Van Helden and eventually made its way into the pop charts, which by that point was always going to be game over for any credibility. So Solid Crew being the dregs.