There's an increasing tendency for the consumer rights groups to wade in (when pushed by howls from some of the public) and start investigating every single element of unbundled pricing structures.
It's happened recently in Europe with nasty airlines being told they can't charge for a second item of handluggage (AFAIK new rule comes into force next year).
..The airlines pointed out that carrying two bags is a personal choice, but under pressure from consumer groups the EU decided the charging was wrong and outlawed it, so in effect the minimalist packers will be financially disadvantaged next year.
Ah, but what the heck, that's another "scam" the consumer groups and politicians have stopped and the creep back to regulated fares continues.
I do think there's almost a case for the airlines (and by extension the airports) going back to bundled fares with everyone paying their way...
Say UK Med return for £400 return, regardless of when you book, what flight you book on and what luggage you bring. In the context of this thread the airlines would be then be able to pay handling/passenger charges without squealing and there would be no need for drop off fees...