There are lots of reasons not to travel in coach.

I don't travel in coach longhaul because I'm unwilling to suffer and be squashed into a seat for any period of time.

I've also been involved in long travel marathons where you seem to go airplane -> meeting -> airplane -> different meeting -> airplane -> yet another meeting.

Being productive during those long hours on the planes was well worth it. I've seen entire deals re-written inflight

There are people who are effectively commuting back and forth between North America and Asia. It's hard to find good people willing to do that every other week if they have to sit in coach. Effectively such costs become immaterial to the costs of NOT having the right person in the right place at the right time.

Steve