Outlook is a business exclusive these days?! Outlook used to be included in the most basic version of office back when I still used microsoft office.
Will be removed from the next release. Then you can’t connect to your own exchange server anymore and are forced into 365 when you want a desktop app.
I’ve only ever used Outlook when forced to by an employer and I find it a dreadful application to use. I would guess that most people prefer something else. I would imagine that most people tend to stick with the default email app on their computer (no idea what that is on Windows as I’ve managed to avoid having to use Windows for 7 years now).