You can always design around that. I know I'm mostly locked in when I deploy a classic GAE application or when I use the datastore (there is AppScale, if you need).
If what you are running is a virtualized version of your physical DC infrastructure, you can probably deploy it anywhere with very little trouble.
Google doesn't seem to be serious with their managed DBMS solutions. The PostgreSQL version is still 9.6 even though 11 has been released, whereas AWS already has pg 11 available.
We are having A LOT of troubles due to lock in with Google Cloud (particularly GAE and Datastore, but also Pub/Sub) and it is really not fun at all...