Blame it on the public and their dorked-up mentality! They refuse to pay for an outright higher fare that will allow the airlines to survive and make money, yet the airlines have found a way to still extract it from them. While I don't agree with how it's being implemented, it is a necessary evil. I'd much rather see a fare that includes EVERYTHING, including taxes, and then get all the other services for "free", but apparently the public doesn't want to pay that fare, so they'll pay it in increments until it still equals what's needed to survive and make money.
As an aunt of mine used to tell me, "honey, nothing's free!".