If those who can't do teach; Then what does one do If they can't teach?

Become a republican politician.

They become college professors.

As a college professor and practicing artist and designer, I call bullshit on the premise of the question.

To be fair, I have met professors who’ve barely or never worked in the field, only taught — but I tend to hang with those who’ve had a busy professional life, stay current in their industry, and teach.

I’ve either been a full-time designer and part-time teacher or full-time teacher and part-time designer for nineteen years. And, I was a full-time artist & designer for twelve years before that.

@cookieman Thats why I said “if”.

Go into government.

They become managers.

In all seriousness, I’ll call B.S. on that too. In grad school they often encourage students to teach because when you have to teach it forces you to learn the material very deeply, which is a requirement to you know…do things. This caries over to work where the “technical specialists” in an area are often required to teach the subject to others in the same area on a regular basis.

If you can’t dazzle them with brilliance, baffle them with bullshit.

And if one can’t even write? Dream.

They suck it up and teach anyway :P That’s how it’s been for me, as a grad student who’s also had some teaching experience. Of course I’ve gotten better the more I’ve done it.

See above.
If they can’t do, and they can’t teach, many go into politics.

That’s an old Woody Allen joke

“Those who can’t do, teach.
Those who can’t teach, teach gym.”

@seawulf575 totally nailed it. When I was in college my chemical engineering professor thought it necessary to take class time to tell us “You shouldn’t expect much from your teachers because we didn’t get our jobs by being good teachers.” As if it were our responsibility to avoid exposing their ineptness. It then occurred to me that exactly half of my professors had said in class that they didn’t know what to teach or how to teach it.

The OP is in fact an insult and I would expect a teacher to demand professional respect, or to go someplace where they at least didn’t insult their teachers.