Several reason, perhaps one of the best was because of capitalism. (;->
Original question was anyone know reason why SLRs won. (Wilson Picket)
While there's no doubt that camera companies exist to sell you a camera, and this forces them to keep changing the camera they sell you... I think you're over-analyzing it (or maybe not...) Capitalism worked because people flocked to SLRs. If SLRs didn't offer some kind of advantage over rangefinders, they would have sat on a shelf, discounted, and it would have been a failure.
I don't know for sure, but I'd say zoom lenses had a lot to do with the SLR winning more than anything. The general public - even many pros, prefer to shoot with a zoom lens. This has carried over to the digital age. The shift was that you don't shoot indoors in ambient light with a fast lens wide open and slow shutter speeds with grainy high-speed or pushed film, silly! You shoot at f 5.6, at 1/125 with
a flash. So expensive fast lenses didn't matter so much - and hey, you can have all those focal lengths rolled into one with a zoom! No carrying 5 lenses around with you, fumbling to take one off and put a new one on... just use a zoom! A RF focusing system can't accommodate zooms - so that was that...
But the switch to SLRs - with their slow zoom lenses and blinding indoor flash systems, really set photography back... A leap forward in technology, a leap backwards in aesthetics. Suddenly, instead of those evocative candids (even if they were by accident) taken in natural light with an unaware subject and a nice blurred background... you got awful posed shots with blown out foreground objects and everyone all uncomfortable and nervous...
Later, when rangefinders and fast primes were so out of fashion great kit could be had as cheap as chips, they were "rediscovered" along with fast primes, selective focus, black and white, D76 and Dektol - helped greatly along by the internets and sites like RFF....
Leica - philosphically at least, was right all along. The best photographs are made with natural light, with an unobtrusive quiet camera, and as fast and as good a piece of prime glass that you can get... a 35, a 50 ... (and really just one of these based on your personal preferences...) "maybe" something longer for the occasional portrait. That's it. That's all you need. (And why I sometimes laugh at the ridiculous lens collection some people have for the same camera system...)