Of the top 10, only Java has experienced a year on year drop.

So, at least some of the gains are at the expense of Java.

For C and C++, you're probably not going to reach for Python as a replacement. It's not like in the 90s when these were considered general purpose. If you're using them these days, it's more likely due to needing to use them.

Java is still used for a lot of other things where a language like Python would be fine and likely more productive. Also, I have a feeling that the large growth in go from #20 to #13 likely also came at the expense of Java.

That, and the pie is growing. Python is taking a larger share of the larger pie.