Actually there is an article in the NY Times on this very issue today.
I found only one good argument in the article for the airlines to be willing to infuriate fliers with extra fees. All the others were, in my opinion, bogus - even if slightly true (I would agree that less baggage means less lost bags, but that has always been a problem of hiring and keeping incompetent people, not that there HAS to be 2% lost baggage. Some air carriers are well under .5% if memory serves). NO, the one item that makes some sense is that less baggage gives them a chance to ship more cargo. But, if that is the case, why not go into the cargo business and forget transporting humans. Crates of stuff never complain or get sick. Sounds like the perfect business model to me.
I was disappointed in the article because it gave no figures. How much does it cost to ship an additional bag? How much fuel does it cost to deliver one more pound of luggage? etc. Without that info, this sounds like a totally pro-airline story. There was very little about whether the flying public has a case when it gets honked off at the airlines for their excessive fees. In short, a very unbalanced article. Why doesn't someone actually do a piece on the business model, with facts and figures. If it does actually cost $25 to deliver an "additional" bag, maybe folks would quit complaining and anti up.
The article did point out that there have been bad consequences to the airlines of this practice of charging for bags. Folks carry on more which takes more time and causes more injuries. What is the cost of THAT compared to the fees they now collect for baggage?
In the old days, i packed 2 medium or small bags to check, fairly light so I wouldn't strain myself carrying them. Now, for checked baggage, I take a single large bag, carefully weighed to 49.9 pounds. I have one small item near the zippered flap which I can retrieve and stuff in my coat if I'm a couple tenths of a pound over at check in.
I used to carry on a camera bag or at most a small duffle. Now, I stuff an official size carryon bag (looks like what the flight attendants use) and pack it to 39.9 lbs. Yes, I've changed my travel habits. That may have been the airlines motive. If so, they have been successful. However, I don't think it has saved them much fuel and it has cost them ALL of my loyalty. I'll pick one carrier over another now for a difference of $10 in the fare (including the excessive baggage fees). There was a time I had a couple of favorite air carriers. Now I curse them all when I have to fly. I used to smile and sigh as I intently watched every airline commercial. Now,when an airline commercial comes on TV, I switch the channel faster than when (the late) Billie what's-his-face comes on screaming about some kitchen product.
Can't believe the airlines actually have gained much by their recent desperate antics.