Because snow foaming is a massively overhyped fad. The cleaning effect is fairly minimal and you still have to give it a proper wash afterwards if you want an actually clean car. I use Bilt Hamber snow foam at high concentrations and it cleans a little, but nowhere near enough. If you're doing it every week and you have a good layer of wax down then it'll help, but if your car is actually dirty then save the hassle of getting all the gear out and just get cracking with a two bucket wash. After I've run out of snow foam I'm probably going to sell my lance.