I am an American citizen and work in the exact same field. I would describe the field as much larger than you believe it to be (but certainly still rather small

I am an American citizen and work in the exact same field. I would describe the field as much larger than you believe it to be (but certainly still rather small) and have lost jobs in this area to H1Bs. While I'm sure you are exceptionally talented, there's more to the story than "Americans just can't do the job!" The h1b narrative is exactly what you just described. I would say that your company has recruiting issues if you truly can't find qualified Americans to work on embedded security. (Is this a Big 4 company with a crazy hiring bar? That might make sense) There's always more to the story.