Google doesn't have a good track record supporting its products. I have no doubt that GCloud will stick around, but the fact remains that Google has trust problems.
Google Cloud is paid b2b, not free b2c - companies like Disney, Spotify, Evernote build very close multi-year relationships with Google, rely on Google, pay Google, etc. Google Cloud going away would shut down, for example, all of Snapchat.
(work at GCP)