I genuinely wonder why people use SQL Server, is it just because of the active directory integration? Just because microsoft says so?

I mean, its a lot more expensive than Postgres for very very little benefit. Like what exactly is the value proposition? Is it saving developer time? faster? I guess none of those

Back in the day (2000s) if you were a .NET shop it made sense as the providers for anything else were not as good. And probably you are more likely to get those skills over Postgres. And Postgres was a lot more early.

These days a I am not so sure what the case would be other than legacy or very occasionally some feature only SQL Server has. AD would be a big one.

20 years ago, I was a massive Postgres fan and I still am, but I bought and used SQL server for production systems - it was better (particularly in replication), and more importantly had better support as in being on the phone with the lead dev type support.

Today I have no idea about SQL server but if the support is as good today as it was back then it can be worth it.