Sounds like you have the benefit of a nicely designed server and good practices. A lot of companies aren't the same.

Imagine you're a big company with loads of teams/departments multiple different types of SQL servers for data reporting, plus some parquet datalakes, and hey, just for fun why not a bunch of csvs.

Getting data from all these locations becomes a full time job, so at some point someone wants some tool/ui that lets data analysts log into a single thing, and get the experience that you currently have with one postgres server.

I think it's not a problem of scale in the CS sense, more the business sense where big organisations become complex and disorganised and need abstractions on top to make them workable.