Let's use photographers as another example. Any good photographer would still spend a lot of their time in photography even if they had a billion dollars. They probably wouldn't take the exact same wedding photos every Weekend though.
You really can't be a REALLY good programmer without side projects where you get to play around with new technologies, with no deadlines, no managers, no infrastructure, just exploration.
I know there's lots of people who are flooding into this field now just because it pays well, which is understandable, and they might even do a good job and even take pride in their work, but if it's just a job then they aren't ever going to do as well as someone who actually wants to do this for fun. And working with people who are doing it as "just a job" kind of sucks the joy out of the work itself.