Taken out of the context of jobs, I agree with you about what people in academic accelerator physics think of the field (that it is all HEP), but I can assure you that Varian, Smiths, IBA and many more see accelerator physics very differently depending on their focus: medical systems, cargo scanning, whatever.
At any rate, my point is that "accelerator physics", broadly defined to mean anyone who works near an accelerator, doesn't mean that the people involved need to learn anything more than the very basics of what particles are doing inside them, if even that. They are working on the inputs (cryogens, power, vacuum systems) or the results (x-ray optics, material chemistry) but have little to do with making a beam of charged particles do something. So yes, someone working on accelerators might find work in other fields, but it is rarely the people who use words like emittance or phrases like "betatron phase advance" and is instead the people who design and build the cryogenic plant or the modulators. Further, my experience is that the people who most loudly proclaim how fit they (or those like them) are to work in other fields haven't actually applied outside the field.
Also, I'm well aware of what the accelerator stewardship program is, I applied.
If you want to chat about how awesome the field of accelerator physics is (it can be great fun!), I'm totally game. But I disagree that the field is ripe with jobs, especially in the US, nor does it produce candidates who are readily accepted outside the field.