Sure, it isn’t. But most things do not really need a distributed database, just something usable from multiple locations, and Postgres solves that problem easily.
Most vehicles don't need rocket propulsion, yet you can't go to the moon in an FSO Polonez ;)
Just because you, personally, don't have a good reason for using a distributed database doesn't mean there aren't folks who do!
We thought that, built an app on Postgres, got huge, now we wish there was a distributed Postgres vendor on AWS. I’m grumpy Azure bought Citus. Maybe Aurora is trustworthy now? Like 3 years ago I’d still hear about it eating peoples data.
City's is fully open source now.
Sure - but it'd be nice to have it managed for us.