This post isn't intended to provoke anything more than thought.

I don't like first class or business class, despite the fact that (1) I'm 1.94M tall (about 6 feet and 4 inches, I think), and (2) I flew almost 350,000 miles last year.

Why?
First and foremost, in all my travel relationships, I want to be left alone. Your offer of another glass of orange juice is very kind, but if I REALLY need something, I'll ask.

I work for non-profits. While I could upgrade at little or no cost (e.g., using points), it's not a good image for my company.

I don't drink.

I'm a strict vegetarian, so most better-class food isn't of much value. (I also have no taste buds...a result of 35 years as a vegetarian. )

People in first class are no more interesting to me than people in coach. (make of that what you will.)

I find that glorified coach (e.g., United's Economy Plus) suits me fine.

I probably refuse ten spontaneous, no-cost upgrades a year. I'd rather they accrue to someone who places a positive value on them.