There is a fundamental difference between a la carte pricing and fees.
Every breakfast joint in USA will be happy to sell you a side order of two eggs, a side order of bacon, a side order of hash browns, and a side order of toast off their individual items list, but also has the “All American” or whatever cutesy name for the same thing as a package deal. And probably for slightly less total price than the four a la carte items. Pizza places are the same, where the [whatever combo pie] costs a bit less than starting from a plain cheese pizze and adding the same toppings.
OTOH, adding a 2.5% [whatever] fee, or the increasing habit of rolling in an 18% “service charge” (where you don’t know if 100% of that is going to the actual server as a tip), is a whole different thing. And is IMO indefensible.
Further IMO taxes, if any, should NOT be rolled into the displayed prices. It’s better to display both pre- and post-tax prices, but if there’s only room for one price, make it pre-tax. Yes, even for highly taxed situations like hotels and rental cars.
With that background …
I will slightly defend Spirit Airlines’ pricing of seats as a version of a la carte. The plane is divided into zones, both fore/aft and aisle vs window vs middle. Each zone has a different price. No different than a burger or pizza that has some basic toppings included in the price, plus another dozen optional toppings available probably in 2 or 3 price tiers.
The rest of Spirit’s a la carte services, such as carry-on bag, checked bag, food, drink, etc, etc, are individually defensible because not everyone needs everything and some people need zero of those things. The consumer challenge comes in when the conventional old-fashioned airline model was “all inclusive”: you could bring a silly amount of both checked and carry-on luggage, and be fed & liquored up, all for one price. In restaurant terms, that’s like somebody who grew up eating only at all you can eat buffets then as an adult being introduced to conventional restaurants with menus containing both pure a la carte items and combo meals such as salad, meat, veggie, and starch.
Admittedly with Spirit, the collective effect of wall-to-wall a la carte pricing is surprising to most everyone. Which just demonstrates how used we all became to airline ticketing being eating buffet style with a little bit of 10 things heaped on our plates.
Bottom line: Sometimes deciding where the line between a la carte and combo meal belongs can be hard. e.g:
It wasn’t that long ago that every electronic gizmo came with a wall wart & power cord. Now few do, but they do include a charging cord with one end that fits the gizmo and the other end is USB-A or (increasingly) USB-C. Now you need to provide your own USB charging hub. I expect that if industry can ever settle on one nearly universal connector standard, call it USB-U for “Universal” (I just made that name up), then real soon even charging cords won’t be included in the 99% of devices that use USB-U. You’d be expected to provide both the USB charging hub, and the matching [whatever] to USB-U cord.
My bottom line:
There is a good discussion / rant to be had about fees. But IMO it's important to distinguish between increasing *a la carte*-ism, "shrinkflation" of expected accessories (e.g. charging cords), and automatic everyone-pays add-on fees. Both mandatory and [mandatory unless you Karen/Chad to the manager] fees.