Interesting. I think it's the opposite. Because PM culture differs from company to company, I feel like companies interview for PMs with a bias for how they expect their PMs to behave. This would be unlike Developers where companies are looking for folks proficient in specific languages.
I've had friends who interviewed with companies for PM positions and the focus was on their doing great UI mockups. The interviewer was looking for good UIs. Unfortunately, these folks were coming from places where the UI mockup they did was just basic placement of elements to communicate the elements they expected their solutions to use. A seperate design team would later turn their mockups into beautiful UIs
But I also think it's ignorant to say that companies just want folks proficient in specific languages. That might be true for people without much experience but in most cases beyond that (which pay well) people are looking for deep technical understanding of a specific technology (e.g. deep learning) or a specific problem (e.g. scaling large web services).
Fair Point. For experienced hires, companies want technical knowledge of a technology/domain
>>>> But if you aren't requiring your PMs to be technical, I mean the sheer amount of people qualified to do that job (even with stipulations such as "knows design")>>>
Well, for experienced hires too, domain specific knowledge is also relevant for PMs.
It's also just a case where lots more people are qualified for this kind of job so it's not as hard to fill a position when the need arrises.