This thought occurred to me as I was zooming a few miles over some part of the blur that is middle America. You may not remember this, but a way long time ago people could check baggage for free when they flew. Now, you couldn't check your entire wardrobe, well, I could but you get my point, but you could check a bag or two without them charging you. This once, coincidentally, quite helpful as I tried to move to Michigan and live out of a suitcase.
However, times changed and, in due course, all the major airlines were charging some sort of fee for the first bag a passenger checked. So, Americans being the cheap blighters that we are, we stopped checking so many bags. But we still wanted to bring our stuff with us, if there is something Americans dislike more than fees it is leaving our stuff behind, so we started putting more stuff in our carry-on luggage, because that was free after all!
Airlines, being the generous souls that they are, even allowed passengers TWO carry-ons, a little bag for under the seat, and a larger item in the overhead bin. And when I say a larger item, I do mean bigger than a bread box. In fact, they allowed such monstrously large bags that they realized that if everyone brought such a big carry on, they couldn't fit all of them in the overhead compartment; thus was born the gate check.
If you gate check a bag, you take a carry on, then allow the airline to check it through to your destination at the loading gate. So, for those of you paying attention, now we are not bringing checked luggage, instead bringing bigger carry-ons, checking those carry-ons (so they are indeed not carried on), and storing them in the space vacated by the checked luggage whose removal heralded the rise of the carry-on. This thought may be funnier in midair when one is suffering travel fatigue, but I still think it is fairly funny.
I also think it is a success of capitalism. Although they reign as monsters among carry-ons, the largest carry-ons are dwarfed by checked luggage. So, we are being convinced to bring less stuff with us on airplanes, which, in turn, makes the airplane more fuel efficient, a true triumph of economic environmentalism!