Doing what you love / care about, at least partially, while still making a living is an interesting task. Also a highly nontrivial one unless/until you've already made a few millions.

One way to do this is instead of watching TV, playing WoW, etc, that is, instead of pleasant but exclusively consumer activities. Seen at this angle, the advice does not look all that bad.

This is not unlike having kids. You don't quit work to have kids; to the contrary, you work harder to give the kids a head start (nice toys, good books, advanced kindergarten). You don't stop working for money, but you spend the money for what you love more than money. If this works for your child, it could also work for your brainchild (which is often less demanding, too).