Meh some people on here get butthurt when you talk about brands that aren't Arrma and to some Traxxas is like saying the F word......
The initial cost of the car is all I can think of. Look at the Sledge vs the Kraton 6s, the Sledge is $700 while the Kraton is $550. You getter better bang for buck out of the box. Both cars have their issues so after the initial purchase the cost of owning both will go up.
IMHO Arrma isn't any better or worse than any other brand that is currently on the market, but having said that I think the 1/10 platform are the most overhyped piles of garbage, I would rather buy a HSP or BSD Racing car before I ever touch one of those cars again.
You can do the same thing with any other brand. This is nothing unique to Arrma. Look at Tamiya, they have maybe a dozen different platforms but hundreds of cars. Every manufacturer of pretty much anything does this. Look at GM, Ford, Toyota, Samsung, LG, Toshiba, Mitsubishi ect.