> I haven't seen a single example of a practical application written in .net core or a company that uses it
We[1] have multiple teams working with it right now (we're strangling our netfx 4.6 monolith), and some of those teams have already pushed their work to production.
The big advantage that I've seen is that it puts teams in charge of their own destiny. I remember the upgrade from netfx 2.0 to netfx 3.0: it was awful. The entire codebase had to be upgraded. Customers had to be upgraded to netfx 3.0. If another vendor futzed with and broke the machine.config, we'd break. With netfx you are perpetually behind the curve and at the mercy of the admin, especially if on-prem is a concern. netcore is xcopy deployment, runtime and all. You can use netcore on alpine[2] (netfx only works with Windows containers).
> there isn't any reason for them to focus on it.
1. Even if nobody was using it, I bet Microsoft would use it themselves. It is so much better than netfx.
2. Azure. It does run outside of Azure, obviously, but the Azure integration in VS is a powerful bait and hook.
Plus, for something that there's no reason to focus on, they are certainly putting a lot of focus into it. Even if I haven't figured out the true reason to focus on it, there clearly has to be one.
> There just aren't many available alternatives to the frameworks and packages
That was an issue up until, maybe, a year ago. Most packages have netstandard (a build target that works with netfx and netcore) support nowadays. If they don't, they are probably unmaintained.
[1]: https://www.k2.com/
[2]: https://hub.docker.com/r/microsoft/dotnet/