Assume there are is a small number of big players. They want to artificially keep the prices high. They could make an agreement, but that would be illegal. Assume it would not be illegal.

Now apply your logic: "Would the market sort it out?"

No, of course not.

So why would the market sort it out in other cases of anti-competitive behavior?

Not very obvious but it was a joke. There's a sense (somewhat more common on HN than in Real Life) that the Free Market will result in an ideal equilibrium and egalitarian society, and it's funny to me, because (as you point out) it's so obviously not the case. But someone always brings it up in these contexts, so I was trying to get a jump on it with some mild sarcasm.

need to replace "but" with "b-but" next time :)

Solid technique, but I was going for a different voice, sort of a dramatic pause and a winking 'aha! - but what about the market? Ever think of that?'