I never understand why people don’t pay more attention to “n” in these cases: number of other players.

If there are 2 suppliers in a market, they will collude without algos or private meetings: I can be pretty sure you will not cut your price if I don’t cut mine. The issue there is that there are only 2 suppliers, so trust is very easy.

If there are 100 other suppliers, I know ONE of them will cut their price. So I best cut mine first.

What I am trying to say here is that, algos or not, n is the major driver here imho.

That’s kind of interesting since the US has been very relaxed about falling values of n as long as prices seem ok.