Vanadium 50 said:
Is this a requirement? It is in, for example, some public school districts, where there is a formula for pay involving years of service and hours past a BS or MS. Someone just starting as a school teacher costs (in one district that has their contract on the web) 50% more with a PhD than someone just starting out. (And 20% more than someone with a BS and ten years experience)
Or is this an assumption? Along with the assumption "they don't really want to work here". (Which is still an assumption, despite the abundant validation one can find on PF)
I'm not 100% sure of the thrust of this question, so I'll give the short answer and then expand: It's an assumption.
The longer answer starts with it not mattering what is true and what is assumed because what matters is the actions taken based on those beliefs. If a resume comes across my desk for a no-experience junior project engineering position and the person is a brand new PhD physicist, I'll [wonder why HR didn't screen it out], say "huh?" and then probably not bother responding to it. If it includes a nice cover letter, I may read it, but it had better contain good answers to these questions:
1. Why do you want this job, vs one in your field?
1a. Are you just going to quit if you find a job in your field in 4 months?
2. Are you willing to accept what this job typically pays?
Someone with a BS in physics or engineering physics is much more likely to get a call than a PhD in physics. Yes, there is such a thing as "overqualified".
Note, I work for a consulting engineering firm, not the government, so payscales don't really exist. We bill our clients what they are willing to pay for a "junior project engineer" and we can't have one making double what is typical. We couldn't compete for projects or be profitable with someone like that.
I also work in a lower-end, commodity engineering field, so this may matter more than if you are a physicist looking for a mechanical engineering job in, say, aerospace. There's still a small practical skills gap, but they may be more willing to overlook that and pay a higher salary for someone proven to be really bright. But that's just a guess.