Given the choice of getting either both an equivalent of John Carmack and a completely overconfident, unskilled CS dropout on my team or getting neither, I know

Given the choice of getting either both an equivalent of John Carmack and a completely overconfident, unskilled CS dropout on my team or getting neither, I know which I'd prefer. A great hire is worth far more than the cost of accepting a bad hire. Even in the case the bad hire were completely untrainable and never managed to get anything past a code review, paying two salaries for the output of one Carmack-like outlier is still a bargain.