This thread is slowly filling up with stories of enthusiastic workaholic parents who are disciplined and fit enough to take every single 15 minute break to sit down and get some code out. If you're able to code up a blog engine with one hand while holding your baby in the other, I envy you. I wish I could muster up the energy and discipline to do something like that. But to other readers: for many people this is not…
I am one of those people who at least tries to do lots of extra learning. But firstly, it doesn't necessarily have to be programming: I learn things like math, but also other hobbies (e.g. drawing).
But whether I have time to do things "on the side", the BEST thing I do for my professional career is work for myself, and spend time working on projects that push the edge for me. However much "extra time" you put in outside of normal work hours, normal work hours still make up the bulk of your time, so you have to optimize those.
So like I said, I completely agree with your post, I just think it applies equally well to those people who try to cram in more work on the side.