Many frequent travelers don't check bags anyway. The most frequent travelers have elite status on an airline that might allow them to check bags for free.
1) Business travelers can expense the checked bag fee, so they don't care.
2) Other travelers still have a free option: the carry-on bag.
I always board my flights last for various reasons, and I've noticed how people are literally hanging over the ropes to get in the boarding line when their section is called. It started making sense when the staff would announce that ALL overheads were now full. People were packing even more into those carryons.
Which is why the checked bag fee never made any sense to me. They should be charging a carry-on fee instead. Carry-ons are a PITA for the airlines, with all the time the stowage adds to the boarding process.
They don't charge the people that count. When I worked for an airline, we were told to just ignore complaints from customers who flew less than several thousand miles per year.
For me it's well behind the grudge about them rubbing my ballsack, but alas I can't swim home to my parents and I don't want to have to sit in "time out" for hours so I just keep my mouth shut in the airport until the awful experience is over.