In part, because the Java ecosystem kept getting more complicated. Fifteen or so years ago I was a full-time Java developer, but I wouldn't know half of what I need to know today, and I'm not very interested in going that route. Java kept the language simple-ish (not really, because they have added a lot on top of it), but the stack grew rapidly, and you have to know the tooling to function in that environment.

Python remains a lot simpler. It is getting more complex, but it has miles to go before it reaches Java-land.