I think for .net developers, this makes more sense. You have an existing .net app, built to talk to MS SQL Server, if the latest version of .net can run on Linux, but your DB can't then you're faced with either managing two OS flavours, or just ignoring the Linux compatibility.

Ignoring Linux compatibility would have knock on effects because Linux is now the platform for so many other tool, e.g. Docker.

Regardless of how easy the 'upgrade and migrate to Linux' story is right now, I think it's vital that MS started down this road. Otherwise the .net framework would be [seen as] finished now, and people would start planning to migrate off it.