Generally agree, but there are some valid reasons for flying business that are not just about having "better" seats. Ever try to work on a laptop on a budget economy seat? Even with a small laptop its almost impossible. On a round trip from CA to Europe or Asia, that's ~20 hours of lost work time, and for professionals who cost the company $500/hour that adds up. Since the high profit business seats allow airlines to charge less for economy seats, there is some advantage all around.
In general though we can always save energy and emissions by making things worse. People can ride electric scooters instead of cars - you see this a lot in some countries, and I've seen a family of 4 on a motor scooter. People can live in smaller houses, have less AC and heat, not eat meat, etc. My preference though is to go the other way and make better technology. We are already seeing wind and solar, and electric land vehicles becoming cost competitive. So far there isn't a non-carbon solution for aircraft, but high speed rail is a good alternative for trips 1000km or even more. It may take a while to find a low emissions replacement for long haul air travel, but I expect we will get there eventually too. Probably hydrogen (once we have the grid capacity to make it) but maybe something else.