Regarding your post though, i think that no one is assuming extremes - you can easily manage a few hours a month to do some mad science experiments. You might even surprise yourself with the outcome or renew your passion that made you take up development in the first place.
You also don't always get the full perspective in your day job - even if you work at an amazing place.
Development isn't a music skill. It isn't about repeating a piece over and over to train your mind, motor skills, and dexterity until you can reproduce it perfectly.
Every day people are pouring tons of new and interesting ideas into this discipline and more often than not, they have excellent ideas which can be shared and studied to your benefit. Take advantage of it.