The whole point of the article is why airlines can't make money - and maybe it's because they are all the same?
So why do you think airlines can't make money?
Because not enough people are willing to pay $200 more for slightly more legroom, nor for better food, nor for this or that or anything else you mentioned.
As the OP said, airlines already do let you pay for as much of this as they can.
Very few people find it worth it.
Many people just don't get how well off they are compared to random person in a random town in the country.
$290. That's a weeks pay at minimum wage.
The whole point of the article is why airlines can't make money - and maybe it's because they are all the same?
So why do you think airlines can't make money?