Well, this truly sucks. I know SONAR will continue to work on my studio PC for the near term and I should have no issues finishing the album projects I have going at the moment. I really hope a "no authorization" version is released for lifetime subscribers, but I'm not holding my breath.
 
I want to know what my options are for Plan B. How would one migrate a half finished project to another DAW? Export each audio track as broadcast WAV or something and then import them all into a new DAW? All the tracks would line up and just work? I assume MIDI would be easy. Of course all the EQ and automation and effects and whatnot would have to be redone, but that's no biggie. It's the performances that matter to me.
 
Thoughts?

I don't know if that's the best solution, but that's what I'm planning on doing.

I wouldn't bother. Some projects will be easy to port, but many will be difficult. Last time I ported projects from my old computer to a new computer it took ages, and that was moving from SONAR to SONAR! 
 
Just leave SONAR installed in case you ever need to revisit those projects. By the time it stops working, you'll no longer be concerned about those ancient projects, just as I am no longer concerned about my old projects on 10" 4-track reels.

If it were me, I'd acquire the new DAW then start new projects there.  I'm not concerned at the moment even though I have almost 15 years and about 1500 songs that are in Cakewalk format.  I'll HAVE to keep the software on some computer to go to the legacy stuff at some point.  Such is life. 

I've heard export as an OMF ... then try importing on a different DAW platform.
I only exported omf when a wave track I needed to know the BPM of a wave file recording.

Mix/bounce all of your tracks individually and keep the wave files in your project folder. This way you can import your bounced individual tracks in to any DAW without losing the sound of plug ins that may have stopped working.