I'm not sure about crappy quants. Some people of the "quantitatively inclined trader who has learned Python" variety are never going to be good at the engineering side - it takes years to learn to be a good software engineer, and that's not a good use of time, for them, or for their employer. But they can still do useful work.

The trick is to figure out how to work effectively with those people. Build infrastructure that keeps them on the rails, refactor their code, push them in the right direction, tell them when they've fucked up, teach them little things with high leverage. As long as that doesn't turn into being their slave, that's fine.