To be honest, 90% (probably more) of the engineering that I know, was not through my Degrees. In fact, despite my Masters being in Radio Communications, the vast majority of useful (both practical and theoretical) knowledge I have in RF has come from amateur radio. Equally, without my formal education, there would be gaps in my abilities. It provided the structure to tie together what I knew from elsewhere. I sure as hell don't know even 1% of what Jeri does about semiconductors, FPGAs and high quantity low margin production though.
Talking of whom, Jeri may not have formal qualifications (I don't know either way) but she is an engineer through and through. Some people just are, we seem to be born this way. Somehow an engineer knows another engineer, irrespective of gender, nationality, skin colour or language.
By "all the way down" I don't mean that they can mathematically model quantum effects in semiconductors. I do mean though, that they have a reasonable idea about how each model in the chain operates, and can at least give some sort of approximate model to that operation. This does not mean you have to have the ability to perform symbolic calculus.
I thought I should watch BH's latest video, the one tearing down a classic Mac. He ponders on how old the hard drive is, turning it over in his hands. At 7m10s it shows you a nice close-up of the HDD with at least 6 1990 date codes on display, but still can't work it out. He seems amazed that they did SMD "back in the 90s". Hmm. Very good presentation skills and a clear voice though. Also, for a bloke with a workshop stuffed full of expensive gear, he has a pretty poor set of basic tools.
Total appreciation though for his ability to produce new content every week. Even with a big sponsor and assistance, it takes a lot of work. When it gets to this level of production, the guy on screen is usually just a hired actor, reading out a prepared script. Maybe with an engineer off-shot giving advice. Talking of which, I think BH's show would probably be better alongside an engineer, with Ben providing the charisma and presentation, and the engineer providing tech content.
Towger, the reason many of The Amp Hour's guests are not formally trained engineers (although I'd probably not totally agree with that) is because we are dull buggers, who can't really talk about the work we do. Most engineers are tied up in NDA agreements, even for non-military contracts.