I love programming (not just playing with code) and making excellent things with code, and electronics and mechanisms. I get paid to be good at it and help others do so as well, and I love that, too.
All that said, the author’s warning is well heeded. There are things I’ve built and run at my own expense. They could be commercialized, but that bit doesn’t seem like fun to me (I don’t need the money, so there isn’t a problem there to solve). I could give them to someone who would commercialize them, but that would create problems for the new owners and old users - so again, not fun.
Perhaps there is room for both - pure fun and enjoyment without obligation or commitment, as well as the commercial tangible benefit to others (i.e. paid for).