The title is a play on the old saying "Those who can't do, teach".

Whether this is actually the case or not is debatable.

Back in junior high one of the classes was marooned into doing a skit on a school event day. The punchline of the skit was an extended version of the saying - "Those who can, do. Those who can't, teach. Those who can't teach, teach PE. And those who fail at that, end up as head masters."

The head master at the time was an ex-PE teacher.

Being a good dev requires long term commitments and delivering.

Teaching is a serie of small sessions, each connected but still, they have their own close little finish line.

So if you are a procrastinator or have a hard time finishing, you may be a good teacher and yet a mediocre dev

Maybe I'm a good teacher because I'm a mediocre developer?

I mean, people are bad-to-mediocre when they begin to learn something per definition, so when I teach them, I teach them from their perspective? :D

I actually would see teaching as the longer term project without the small wins you can expect in programming.

When you end a lesson, you win. Always. There are very few ways to lose at a teaching moments if you are good at it.

I can code for several days before having something that will make someone smile.

As the child of two teachers I vehemently disagree with what I consider your inaccurate and wholly unsupported supposition.

Except i'm a dev and a teacher.

And i have yet to met a teacher who's anywhere close to have the deadline challenge a dev has.

Somebody not learning is a failure but that's life. A line of code not working on time, well, that's the entire product not shipping.