Not knowing if you paid to choose your seat or baggage at the time of checkout is a reading comprehension issue.

There's a valid complaint that they all game what's included/excluded at the listing price so they sort better in the fare compare websites. But once you go through the sales funnel, if you read, its very clear what you are getting.

It's not about reading comprehension or the lack of it.

It's saying the list price is $100 but then you have to invest time and provide information during the checkout process only to find out on a much later step that the list price is no longer the price you were given.

You're being lied to about the list price which makes it harder to compare prices at a glance and companies are preying on you through a form of "the sunk cost fallacy"[0] in that you're more likely to finish checking out because you've invested so much time already to get to step 6 / 8.

[0]: https://simple.wikipedia.org/wiki/Sunk_cost_fallacy

This is not what airlines do though. The price on google flights is the exact price I pay to fly because I don't check bags or choose my seat. Just because other people do buy those things doesn't mean they have to or were tricked.

Just because the trick doesn't work on you because you don't do what most people do doesn't make it not a trick.