700 to 2150 in a few months??????? For whoever this person is, the world championship title is waiting.
Automatically identifying such amazing accounts (maybe chess.com would want to invite them to top online tournaments!) would be easy in principle... but for a site that can hardly get basic functions like spell check and an even number of black and white working, I can see why they haven't tackled anything like this yet.
But maybe in the future they'll be able to quickly identify such amazing players instead of allowing them to play in obscurity, and probably over 1000 games in this guy's case.
I don't find it that easy to be honest