There is no shortage of Linux devs. If there were, two things would be true:
1) salaries for Linux developers would be going up
2) people with two decades of Linux development experience would have no trouble getting a job
Neither of these is true. Ergo, there is no shortage of good developers with Linux experience.
Pretty much every Linux job I've seen posted in the past few months requires (that is, not "nice to have" but "requires") a dozen other skills that make up a combined skill set that only one in a million people have. Got Linux experience plus sockets plus Python plus git (this is a clue to what's going on...) OK, you also need experience with OpenGL and have three years CG coding on major animation projects.
People aren't looking for workers, they're looking for replaceable parts. The "git" thing gives it away: rather than burn, I don't know, an hour or two teaching someone the basics of git, or asking them to read a book on it, they won't consider anyone who can't simply sit down and start working.
The specific-industry-experience requirements are likewise a give-away: it isn't enough to have 3D experience, it's gotta be in animation, or they won't touch you, because those skills, man, they aren't transferable in any way.
Bytes used in animation are totally different than bytes used in medical imaging, and your understanding of one kind of processing pipeline precludes you from learning any other. You'd have to unlearn all that other stuff to make room for the new, and it would be at least a couple of days before you're a 110% productive member of the team! We can't have that!
[This is a synthetic example of things I've seen over the years, but it's all too prevalent an attitude and seems to be getting worse, and all the while the whining about "no devs available" gets louder.]