I hear you. People are debating checked baggage fees but that's old news.
The carry-on fee is the latest outrageous charge.
It's a "premium" option now because airlines realised people value that their luggage is less likely to be lost and less time waiting at the airport. I bet in a way they absolutely loved the baggage handler meltdown - it's left a scar in people's minds.
Plus a price for checked baggage was set, and luggage is luggage, so the price is now equalised/approaching equalisation
Ryanair/Wizzair/Easyjet will charge your for that space for your backpack under your seat soon too, mark my words
On a return flight between Luton and Budapest, sometimes budget airline will ask for £40 EACH WAY for that small 10kg bag, which I find absurd
I understand supply demand etc, just noticing that what you get seems to be smaller and smaller each year