This isn't quite true. Python was certainly Guido's passion project, and it started that way. But early in its life, it was funded by the United States government via CNRI (under Bob Kahn).
At every job Guido had subsequently, he had at least some buy-in to work on Python, and some coworkers were also paid to work on Python.
There was a core "PythonLabs" group (I think including Jeremy Hylton?) that apparently moved from CNRI to the a startup BeOpen:
At Google from 2005 to ~2014, Guido nominally had 50% of his time to work on CPython, but that's pretty fuzzy because he was really productive in any case. (I was his officemate for a couple years during that time.)
At every job Guido had subsequently, he had at least some buy-in to work on Python, and some coworkers were also paid to work on Python.
There was a core "PythonLabs" group (I think including Jeremy Hylton?) that apparently moved from CNRI to the a startup BeOpen:
https://www.computerhistory.org/collections/catalog/10273876... (I watched this whole video, there's also a couple Lex Fridman videos)
At Google from 2005 to ~2014, Guido nominally had 50% of his time to work on CPython, but that's pretty fuzzy because he was really productive in any case. (I was his officemate for a couple years during that time.)
https://en.wikipedia.org/wiki/History_of_Python