What has hurt more is the vast number of "spec" motors that came along with the brushless reveloution! 21.5, 17.5, 13.5 & 10.5. It was much less expensive and racing was just as fun when there were two, 27t & mod, period. Almost all of the 27t motors were close enough to make racing close and if you want more speed, run modified and drop whatever you can handle in the car.
People will complain that the Nimh and brushed are an unfair advantage over lipo, but I contend that the new tubro boost unobtainium speed controllers are just as unfair. Spend a couple of hundred a season for new Nimh packs or a couple of hundred every 2 or 3 months on the latest speed controller.
Go back to two motor classes and you will ultimately end up with more racers.