If your product or project is big enough to require the scaling and capacity that GCP offers then you’re also probably big enough to be risk-averse about predicating your product’s viability on a platform you don’t control. The way I see AWS and Azure’s success: they replaced server colocation, dedicated server rentals and shared hosting for application hosting because they eliminated the costs and burden of systems administration and hardware maintenance. If you’re a company that did move to AWS/Azure - provided you stuck to their commodity offerings (App Service, EC2, RDS, Azure SQL, etc) you can move back to your own hardware just fine. For other things like S3/Azure Storage which are hard to move in-house, at least it’s easy to separate that from the rest of your application.
But what does GCP have that is cool - but without associated costs of what is essentially vendor lock-in? Without a solid contract/guarantee from Google that some binary I wrote that uses a GCP-exclusive service _will_ be supported for a minimum of 2-5 years it’s hard for me to justify risking it.