Zag...You've actually been having pretty typical casualties of any car... When I raced Tamiya cars many years ago I went through a fair few parts to start with...it's actually called the 'breaking in period' for a reason
It was partly poor set up and partly poor driving. I simply was hitting certain challenges all wrong, going to fast on some things, breaking to hard on others...One of my main issues was I was always stripping spurs and pinions. I was always blaming the quality of the nylon the spurs were made from till a friend pointed out that I subconscious used to slam the car into reverse quite a lot...was just a twitch reaction to certain driving conditions. It was this reflex that was stripping my gears
I also had a habit of trying to steer on landings...I would already have steering lock on as I touched down from a jump, granted when this worked I could sometimes get onto an inside line very fast...but actually what happened a lot more then I'd admit was I broke the front hubs...Again I over looked my habits and blamed the plastics
Basically look at how you drive and of course be mindful of other drivers...they can be idiots
J