I think also: AWS started the industry so first mover advantage and a hell of a lot of products in the space and experience. Azure (MS) has every corporate in the world (nearly) using is on prem AD so they would have picked up tons of easy Azure clients just extending their corporate networks to Azure AD.
This is much bigger than any "google killing products" issue. Azure got a lot of ways to push itself in, and reaps a lot of possible clients by being first party windows solution for companies that have a lot of windows stack.
AWS has the first mover advantage and enormous brand penetration - it's literally the "you can't get fired for choosing AWS" (instead your company might fold due to AWS bills, but you'll be clean).
Meanwhile Google seems to be much less known in cloud infrastructure space - people think of Google Apps/Workspaces, not GCP, and they seemed to have serious problem getting to clients. I know I was quite surprised by the available stuff and low prices when I did my first project on GCP back in 2016, and generally I've been pleasantly surprised except by their horrible billing support (Google can't into actually getting paid?)
They are in this funny situation where they constantly seem to be lacking fully blown virtuous cycle of adopters and supporting companies, despite having some of the best options on the market - but I think the real issue is that they are neither the first mover (AWS) nor "canonical windows source" as with Azure.
I agree with the first point but can you cite some examples for the second. I personally feel they are/should be most developer friendly company considering they are purely engineering driven.
A lot of it seems to be the vastly different quality of documentation and support based on programming language. Where AWS seems low level enough it doesn't matter what language you write your software in, and Azure has made "bring your software no matter what language you write it in" a very explicit message even in its high level cloud offerings, Google gives the strong impression/ego that there are "right languages" and "wrong languages" and they aren't going to support you well (or possibly at all) in the "wrong languages".
Some of that impression is leftover from the way App Engine handled things and the first impression that left, but even GCP documentation itself still seems to struggle outside of "Google approved" languages.
Disclaimer: I interviewed with GCP as a .NET developer with a lot of experience in .NET to try to improve the situation. I got a lot of nasty ego directed at me that interviewers didn't trust my technical expertise because it was in such a "gross" stack and didn't know how to interview me technically. I personally saw that as direct evidence for why I'd never use GCP.
Why would the one imply the other? The Spartans were the most military driven nation in history (possibly excepting the Mongols, who are another fine example) but they weren't exactly open-arms to foreign soldiers..