[samhoggnz]

From my experience, the boarding problem is pretty specific to the US, where everyone seems to have carry on bags perfectly sized to fit the overhead compartments, of which there are not enough to satisfy everyone's need to not check in any baggage (and thus avoid check in charges)

In my opinion the solution would probably be to discourage as much bulk in carry on, rather than herding cats at the gate.

[kylec]

Completely agree. It makes no sense to me that you have to pay to check your luggage, while carry-ons are free. It definitely should be the other way around.

[threedaymonk]

Each checked item costs the airline: moving them around requires labour and equipment, and there are further expenses dealing with the inevitable proportion of lost, stolen, delayed or damaged bags. It probably shouldn't be surprising that they seek to pass that on.