I don't think I have your level of Zen yet, but I think I am getting there. Certainly closer today than I was 1,2,3 years ago.
I think you make an interesting point. This job isn't what I originally envisioned, but I think I have come to appreciate it for what it actually is. I think there is a period of grieving you go through when something you are really committed to that took a lot of effort to achieve isn't actually what you expect. A kind of buyer's remorse if you will. That grief manifest itself as a frustration and anger that a lot of people feel.
But like the actual stages of grief, you hope to eventually reach a place of acceptance. Sure, the future of the specialty seems fairly grim, and I wouldn't recommend the specialty to a student who still has choices and will have to spend more time practicing in the future than I will.
But all that being said, right now, at this moment: the job still offers good pay, good security, and interesting work.