My understanding from my readings in the field of mythology is that the parent post is precisely correct: Campbell was an enthusiastic amateur who did a whole bunch of cherry-picking to suit his passionate holding-forth on the topics, but without systematic study.
If he was alive today, he (still) wouldn't be a PhD, but he'd have a YT channel, a vigorously active twitter page, and maybe have penned a couple of D&D modules.
If he was alive today, he (still) wouldn't be a PhD, but he'd have a YT channel, a vigorously active twitter page, and maybe have penned a couple of D&D modules.