I found an article here and it describes how even though you work hard and keep hacking away at new technologies at home that you probably won’t get any better – you’ll never be the uber programmer that you dream to be.
I’m inclined to disagree with the premise that learning will not make you any better – not for the fact that it won’t, the person writing the article appears to have some pretty strong evidence to back up the claim.
However I believe that NOT working hard out of hours and hacking away at the “cool new APIs” etc will have a seriously negative impact on your career. Sure you may not be getting any BETTER but you could be getting a lot WORSE. I believe that while all the hacking and playing I do (and I can only talk from personal experience) may not make me better at programming the experience it provides makes me better at getting my job done. On top of this trying to keep your head above water in the technological sense may be the only thing that can be achieved by extra-curricular study and exploration but that is nothing to be sniffed at.
In short take the advice in the linked article to be a lowering of expectations and not a call to abandon all hope – that drive to become the best may well be the thing keeping you in a job over the next few years.