I think rather than state an average time to get through the airport and on the plane and have everything break down the second it gets congested they are going

I think rather than state an average time to get through the airport and on the plane and have everything break down the second it gets congested they are going to recommend a timeframe that should get everyone on the plane even in the worst case. Airports/ airlines want to get planes out on time, wasting moe of your time makes that easier for them.