Neon is 100% compatible from Postgres b/c we didn't (or almost didn't) change the Postgres engine.
CockroachDB already does true scale-to-zero if that's your requirement: https://www.cockroachlabs.com/blog/how-we-built-cockroachdb-...
Eg: of innovation -> commodity. EC2 was innovative, but is today common-place. S3 was the same. DBs that scale-to-zero have not reached that state yet.
Thanks for the link on cockroachdb - it sounds promising. I wonder what's the minimum self-deployable unit of cockroachdb - will google around a bit.
If you host it yourself, or use their dedicated enterprise clusters then you still have instances which are individual (virtual) servers.
The serverless model has no instances exposed to you and instead is a multitenant architecture that uses a pool of shared compute nodes with a routing layer that intercepts and introspects your connection to load up your specific database context for query processing.
This sentiment is perhaps right, but I was careful about calling out scale-to-zero. We do have options that are zero cost (or pay as you use), but there's a fundamental difference in something that may be zero cost because a cloud provider is using it as a customer-acquisition ploy.
Options like litestream+sqlite+s3, or what Neon seems to be, are verifiable you-pay-for-when-db-is-booted up, else the verifiable cost is storage only.
So the trifecta that will be very productive for masses is 1) database where compute is scale-to-zero, 2)open source or commoditised, and 3) is RDBMS.