Service hasn't declined in airlines. If you spend the same on a ticket today as you would have had to in the 1970s to fly, you receive better service. That's because you'd have to be flying first class.
We just decided over time that we were only willing to pay at most $200 to fly across the country round trip, yet still romanticized the idea of having a great experience while doing so.
Keep in mind that of the $200 ticket price, about 30% usually goes to fees and taxes; not airlines. You should be grateful a system so robust exists. One that can take you across the country for such an incredibly low price, given that your only alternative is to drive across the country or take a train; both taking an order of magnitude more time and cost an order of magnitude more.
How about spending that money to provide better service?
It's not a revisionist history that virtually everyone complains about the declining level of service and increased fees.