Agreed, but many of the criticisms I am reading here are assuming high scaling requirements and invalidating the approach entirely. When there are many business domains that will comfortably fit within a modestly specced database instance.

Even just B2B vs B2C is a huge split. Plenty of specialized ERPs in the world that have relatively few "butts in seats" users but have a lot of data to work through.

Size of the data, read/write ratio, number of "requests"... lots of axes that change how much pain or not you're in by just pointing to pg