You can buy business class. Much better service and much better comfort. But you probably don’t want to spend that much, which is where the problem lies.
I wonder how many people do pay for it vs just get it as a status/points upgrade.
Adjust for inflation, and baseline tickets are cheaper than they were a decade ago, and significantly cheaper than they were a decade before that. The only reason the difference isn't even more significant is that prices are now at the point that it's nigh-impossible to cut anything further and still have a functional flight.