cepheid

If they did, they couldn't fit as many people on the plane. They're trying to maximize the number of revenue seats per flight while reducing the number of flights. Making the configurations "comfortable" reduces the number of seats per flight, meaning that they have to fly more planes unless they want to reduce capacity below what they're trying to achieve now.

More comfortable configurations are not as cost-effective. Yes, they could raise prices, but consumers are very price-driven. Again, witness AA's "More Room Throughout Coach" - it died. The only reason E+ survives is because it is an optional cost that people can choose not to pay, but choose to pay because they decide it's worth it. If people were forced to pay it, they would resent it.

Also, it costs money to reconfigure planes... that's even more money that then must be recuperated through higher fares.