It shouldn't be, but 13 years of corporate subordination and forced creative atrophy puts a lot of people into an out-of-shape state that's hard to recover from. There's nothing natural about this sort of premature mediocrity. If we tear the corporate system down, Bastille-style, we'll see a lot more badass older people, which will be a great thing for the world.
Well I'm here to say that you can break the shackles. At 37 I might still toil in the Java mines during the day, but at night I am learning Ruby, Rails, NoSQL, zsh and other Open Source/less than enterprisey stuff.
I might not be able to debug a rails app as fast as I can a JEE app but I can still grok/reason/solve issues on the platform.
You absolutely can break the shackles, and should. I'm just saying it's (admirably) insubordinate.
From a typical boss-man perspective, your performance is reduced by this extracurricular work. You're probably working late into the evening, and thinking about Ruby during the day. You're probably planning a move to something better.
You can't be fired for that alone, but it puts you at risk of being in the socially excluded, not-getting-the-benefit-of-the-doubt category.
One of the issues with side projects is that admitting to having them breaks the Fundamental Subordinate Dishonesty (http://michaelochurch.wordpress.com/2012/12/12/fundamental-s...). You're "supposed" to be putting all available energy into your job, or at least respect authority enough to put effort into that illusion. Vacation is okay: that's just taking a break. Off-hours work isn't (in typical workplaces).
I remember talking to a previous boss saying, "I've been thinking of starting skunk works project 'X'. Where 'X' was introducing an ORM, JQuery, or cleaning up some old code/modules. And the answer was always "I'd rather you work on the backlog [of features]."
IMHO, he line of thinking where employers want you only grinding on today's problems rather than additionally incrementally honing the skills to innovate is a broken methodology and does not work for software. The barrier to learning these skills is too low to expect people not to want to do these things and it keeps getting lower.
