Quite honestly, how many people under 40 (or 30) keep learning and stay hungry? Many kick back, raise a family, party, ... There's a lot to life, and only so many hours in the day. If you're lucky enough to do what you like, and to have time to enjoy yourself (at work, or elsewhere), you're doing just fine.
If it happens to make a difference, so much the better. But you gotta keep up.
This is not an issue unique to developers.