you only care about the difference in price and the difference in value

Agree with this as a general principle, provided the "difference in value" also takes into account longer-term effects like movement reputational cost.

I don't think individuals choosing to fly business class based on productivity calculations has much, if any, movement reputational cost. On the other hand, a prominent EA figure might accurately calculate that they gain one extra productive work hour each week, valued at say $100, by paying someone $50 to brush and floss their teeth for them while they sit there working.

This is obviously a fanciful scenario, but I think there are lots of murky areas between flying business class and having a personal teeth brusher where the all-things-considered value calculation isn't trivial. This is especially the case for purchasing decisions that can't easily be converted to work productivity boosts, e.g. buying expensive luxury items for the pleasure they bring.

Take pleasure in the irony that your "biggest mistakes", and the way you recognise and write about them so candidly, are actually incredibly impactful through the lessons they teach others (and yourself). This post has certainly induced some self-reflection for me. Thanks!

Very good points, I agree with all.

Don't be afraid to sound negative, honest feedback can save a whole career!