This is a really popular opinion among programmers. I used to have that too. I've met people with that. But I don't think it's true. Somehow the people who believe it all happen to also have jobs and not enough time for hobbies, or are retired professionals, and even then only a few. When I've had periods without work, my motivation went with it. Doing things seems to make you want to do more things. Part of it might be that if you have all the time you need, then you have to stop fantasizing and actually do it, which is of course less fun and more tedious than the fantasy, so what's the point if the reward of good feelings diminishes the more you do? But there's also something about being busy making you more busy.

Some people can work productively on their hobbies without a job kicking them in the pants every morning. But those people are so motivated, they're going to be doing real jobs anyway!

I live in a country with generous social welfare. Nobody is really too poor to pursue hobbies while unemployed. But they don't seem to be doing it. They do drugs instead. They probably feel useless and bad about life. Having a free house and food and healthcare doesn't help. We have a high suicide rate. Uselessness is an awful thing for humans.

Where is all the long term unemployed people's open source software and apps and arts? There's no shortage of unemployed people and those hobbies cost almost zero money, just time. So why aren't we already flooded with them? Or are we?