The reason Traxxas is everywhere is because they spend lots of money on advertising, and, because they make it very easy for stores to carry their stuff...they don't charge the stores up front for stock. I don't know if they're the "fastest name in radio control" but they certainly are the most ubiquitous. The 300lb gorilla of the RC world. Consequently, every after market manufacturer makes "upgrade" parts for Traxxas. But they also make parts for Associated, Losi, and Axial....
As a busy family man, we understand your time restrictions. You don't want to spend a lot of time online researching, or looking for parts. (Although, Tower Hobbies dot com, is the 300lb gorilla of online RC) So yeah, if you have a hobby store nearby, you'll probably want to patronize them. That's perfectly ok. We're not saying to avoid Traxxas. But if you're serious about the racing thing, you really need to talk to the other racers at the track, see what they're running, and find out about what classes the track supports.