A Ph.D. is something that anyone can do with a bit of patience and effort. Does that mean we should shift the bar so it means professors are geniuses? No. I don't think any arbitrary qualifications make you a genius.
I think that depends on the field and on your definition of “anyone.” I’d bet against an average 100 spatial/math IQ person being able to get a PhD in math or physics, even if hardworking and patient. They would probably be something like 2.5 standard deviations below average and while IQ is not the end-all and be-all, such a vast gap would make it extremely hard for them.
I think the bar should go much higher, somewhere around Feynman. And remember that’s low according to Feynman’s own standards: he didn’t see himself as a genius.