Not really. Basic chinese guns - like umarex - cleaned and re-shimmed are pretty much on par performance-wise with more expensive ones.
I always mention that the most accurate out of box gun, after cleaning, I ever held was a Boyi G36c and I've held quite a lot of guns.
Aesthetically cheaper ones are usually not that great, but there are exceptions too.
On wear and break downs it doesn't matter if it's cheap or middle range. A G&P will break down sooner than a chinese one in general. But that's only statistics. A specific gun will break down randomly. High end ones, like Marui do work fine for years most of the time.
So if you get a cheaper AEG, clean it, get a red dot and use proper BBs, you will get the performance on par with any gun. From that point it is your skills that need upgrading for some years. When you have the experience, you can be more effective with the crappiest gun ever than most of the players.