It's an extension of "if you can't, teach" I think. Perhaps there's a second verse to it, like with "Jack of all trades, often better than master of none". If

It's an extension of "if you can't, teach" I think. Perhaps there's a second verse to it, like with "Jack of all trades, often better than master of none". If you can't, teach, and if you can't do that, go into politics.