Yeah, but what are you saving all that money for?
I agree that not everyone wants kids, but what for? I can see the world now, when i am young and able. I can walk 30km a day, everyday if I want....sure, I will have blisters but I can do it. I don't think I want to be doing that after retirement.
You don't need to be a millionaire to travel and see the world. Sure, if you want to fly first class everywhere, but is that your reason? To go mortgage free in 5 years so that you can travel in luxury? So is it the luxury that you want or actually see the world? I can guarantee you the view of whatever world wonder you are looking is identical whether you are rich or poor.
You are entitled to your road that you choose at life, as am I, but I have to disagree of your "list" and call that a life worth living. Some of them i can get onboard with, but some are just sad.