no matter how much money i would make, you will never see me flying first / business class before i'm 40

you can use the funds in like 1000 more productive ways than buying comfort for a few hours

a cost of one first class flight can buy you a year of workouts with a personal trainer which will delay the necessity for sitting in the first class for another 5 years

pure destruction of capital

I fly business class all the time on points (mostly internationally), agree with your point though, would never pay cash (or at least not until I have a lot of money)