It's not a dominant database anywhere on the outside.
(What's that? Well, if you ever walk into a place like a gigantic oil refinery, you'll see a bunch of people working there. If you look long enough, you'll notice that each of them have an expensive-looking radio ("walkie talkie") on their hip. Some of those radios may be my fault -- and of those that are, there's an MS SQL database that knows exactly how it was programmed. But I didn't pick it; that's just how the system operates.)
It’s completely dominant in its industry and has no real competition. Pricing starts at $200 a month for the most basic, single user setup and goes up (way up) from there.
And no, it doesn’t work on ARM, at all. I tried.
However since we now got the tools for running on both, and experience migrating, we might be moving to PostgreSQL at some point in not too distant future. Managed MSSQL in Azure is not cheap.
And "Holy crap, this is not cheap" is why I see plenty of companies transitioning off MSSQL.
Microsoft is heavily investing in Postgres in fact which is why they bought PostGres sharding company, Citus and looking at commit history on PostGres, they have several employees actively working on it. They also contributed DocumentDB which is Mongo over Postgres.
It will take a long time to die and Microsoft will still continue to do little work on the product and stack your money in their vault while giggling.
They have all been dotnet ecosystem, but self hosted rather than Azure
I think the latest versions of SQL Server also run on Linux now.
Very seldom I use something like Postegres, last time was in 2018.
