I don't think you can. My takeaway from this discussion is definitely that GCP is only suitable for toy projects, and not for serious production stuff that requires continuity.
I’m pointing to this as evidence https://cloud.google.com/customers
I feel like a lot of the problems that people run into with GCP are avoided with two main components.
Number one you should look seriously at the “enterprise” designation for different products and services if you are looking for long term stability and guarantees about the future (details: https://cloud.google.com/apis/docs/resources/enterprise-apis) and secondly you need to buy actual customer support as an add on if you want to avoid the “I had to hit the front page of HN to actually speak to someone” scenario https://cloud.google.com/support
the main problem with azure/aws/gcp is that their parent companies will track everything you and others do, and then close every related thing because they have enough market share to not give a fuck about you.
There are more than enough blog posts of enterprise customers running into random issues with the big thing, buying "big three, promise edition" isn't much of an assurance.
I'd suspect most of those customers have rapid migration plans written up. For a reason.
I can assure you from experience that most large customers do not. For either major cloud, most large customers will have adopted proprietary services like AWS Redshift or GCP's Cloud Bigtable or Bigquery. None of these have anything like the possibility of a "rapid migration".
Not sure what to say in response here…