Presumably because the other features of OpenBSD bring in some benefits to OpenBSD fans. Also you can always develop on your OpenBSD desktop (with the Linux shim) and then deploy to the server without the Linux shim.
Many of us that enjoy UNIX, regardless of its flaws[0], and do not appreciate a GNU/Linux monoculture, similar to having Google taking over the Web with Chrome OS forks.
[0] - Remember that its creators moved on from UNIX and C, creating other systems they saw as improvements on their creation.
My question was more nuanced though. It seems to me that in the past 10 years or so, openbsd didn’t invent very much. Of course that I agree that there are some punctual things where openbsd was first but that’s not the case lately. So it’s mostly a catchup game with linux features and compatibility needs for running linux software. If you open now the HN front page you will see one story about openbsd importing linux drivers and another story on openbsd struggles to support wine - and basically how wine developers don’t care too much about that.
Hence my question, if most of the effort is put to catch up with linux features, is it even worth anymore? If I want to use linux from 5 years ago, I could just do that. Putting so much effort and time into developing a linux feature clone just in case linux becomes evil, also doesn’t make sense, because you can fork when you see this. Licensing wise even less, I think there’s now a mixture on both sides.
So please take it as a genuine question, not as criticism or anything.
Just like others might favour Illumos, Aix, z/UNIX, macOS or whatever take on UNIX evolution.