I've flown on average 250K miles per year for 15 years. If I had done that in Y I would have significant health issues. That's all the justification I need. I do fly in Y on PtP flights of 2 hours or less. Even then, if I have a big guy next to me it takes me about a half day to fully recover. On a 10 hour+ flight it would take a week to recover. That's just my personal physical issue and we are all different.
One other point is that with my millions of miles flown, I have of course been through many airline mechanical and weather issues. As a biz or First passenger, and top elite, I am always taken care of before the back of the plane. Many times I arrive at my destination hours or even a day before the Y passengers make it. The best example of this was on a UA LHR-LAX flight. We were stuck at the gate at LHR for about 2 hours when a UA agent came up to each of us in First class and whispered that they had a seat for us on the NZ flight going to LAX. They said that they were whispering because as soon as we got off, they were going to announce to the rest of the plane that the flight was cancelled and they would be re-booked on a flight the next day. I made my meetings on time, the people in the back did not.