exactly, outside of work I meet some people who are nearing retirement at 25, and others are full of life well into their retirement. My great uncle was still fixing his car at 80!
I learnt c#, c++ and c just after uni (with only BASIC as prior experience) whilst working primarily as a physicist, and am now a full time software developer. As with any learning, you find the best people around to learn from and put the effort in. Changing teams reasonably often enables you to cherry pick techniques and ideas, whilst bouncing your own off others.
It also helps to ask your employer for as much relevant training as possible. Understand the technologies that interest you in particular through your own reading and practice.
Of course if you really can't be bothered to at least keep up with the cutting edge of technology (or invent it!) then perhaps you should think of a different career path.