Everyone thinks they need a data lake when most people just need a data pond or data puddle. This is made worse by the industry disappearance of the DBA role and compounded by the fact that PG is not especially easy to tune.

All of this to say that a ton of people are on some sort of managed cloud postgres where the compute is almost always separated from the storage even for the small instances.

Neon et al. will tell you they scale, and I am sure they can but the number of enterprises that actually exceed when can be put on a few large servers in pretty low. You gotta lock them in early so their orgs never develop the expertise to move off on the off chance they get big.