So the question then is what are those services for?
You basically just proved my point: things aren't cheaper if you have to factor in employee cost.
But, really, I'm not trying to prove or disprove your point. Just noting that there was a situation for us where disk made sense, and we were satisfied with the outcome. Spending 4 hours of person time to save a thousand dollars was reasonable for us in a way it probably wouldn't be for many real companies, because we had comparatively little money and we're willing to work for peanuts.
(Note that I actually share your bias in this one. I both use GCP for my personal stuff and I'm writing this from a Google cafe. :-)