Plenty of people will never, ever, fly RyanAir. And plenty of people choose an airline based on the airline's loyalty rewards program which gives them a higher-quality product (earlier boarding, more leg room, easier changes to flights). It's quite routine among people who travel a lot.

If no one ever cared about airline quality, there would be no first-class or even economy plus class. And yet basically every airline has them.

Yes, airplane travellers are incredibly price conscious--that's the nature of a near-commodity market. But nearly every single flight has a significant fraction of travelers who have paid more for a higher-quality product.