I also find it particularly galling that I can't even put my day pack in an overhead bin because of all the other people who already slowed down loading as they

I also find it particularly galling that I can't even put my day pack in an overhead bin because of all the other people who already slowed down loading as they wrangle their roll-away and their backpack (and purse and jacket) onto the plane, who will drastically slow down exit the same way. I've had to waste more of my life waiting for them than in bag-check lines. Picking up bags at the carousel is another matter. That can take significant time. That is a legitimate concern, even though I personally choose otherwise. I bought a decent bag and pack it properly, so I've never had a problem with damage (~30 trips and still going strong). I've had my bag delayed twice, once for more than a day. There are tradeoffs, but mostly I think people act selfishly by trying to save themselves a few bucks and a few minutes. It's a Prisoners' Dilemma kind of thing. Those are individually rational decisions, but when everyone makes the same decision it ends up being worse for everyone.