It somehow always saddens me to read that. Most devs I know started at a small company who didn't "grew" them at all. I worked 7 years at a small company and never got any mentoring or external education etc. while the "good" ppl I knew from university got jobs at big corps and got even better because they got "grown" right. Who already has is given.
So with a motivated team and some autodidactic learning you can still get very far! Especially since Google and Stackoverflow.com are at your disposal.