[wat10000]

They don't, because competition erases those differences. It's a very competitive market. If people were willing to pay a little extra for a few more inches of seat pitch in economy, you'd have an airline that offered a few more inches of seat pitch in economy with slightly higher fares.

[interloxia]

They do? It's a common upsell for 50-100ish per flight leg.

[wat10000]

Elsewhere people are saying it’s not a realistic alternative because it’s too expensive. I think people just want a better product without paying any more money. I hate cramped economy seats too, and I fly in them anyway, but I acknowledge that I’m deliberately choosing money over comfort and it’s my own doing.