Feenie The idea that "educational theory" is necessary to teach is preposterous. That the left even consider it on a par with the highly technical training necessary to become a doctor shows up the fallacy of their thinking immediately.
Please show me where I said educational theory was necessary. You are presuming, entirely erroneously, that just because I believe that a qualification is necessary to teach, then I must also believe that theory is also necessary.
I don't. I think that the best routes into teaching rely on practical based, professional courses, like GTP and, actually, PGCE.
To make a leap from that to thinking 'sod it. why do a qualification at all?' is insane. I would love for you, or anyone else who thinks teachers can teach with one click of their fingers, to teach in my class for a day - I can guarantee you wouldn't last a lesson. It takes training - practical based being the most useful - but training nonetheless.
And since 50% of teachers already leave within 5 years, given the current terms and conditions, how long do you see these military, businesspeople, retired engineers, classical musicians lasting - without proper training? And come to that, if it only takes 10 months - with a degree - to complete a PGCE (which is mainly teaching based, with bugger all theory, despite what the DM may have fed you) then why aren't all these people you mention applying in droves?
What's stopping them?