the ultimate sport is no doubt the Himalayan climbing.
not only you need to be fit as hell, have superb technical skills, last weeks-long expeditions, but also be prepared to sacrifice your life (as it was the case with the latest winter conquering of Broad Peak). iron man, cycling, etc. - they're nowhere near as demanding as climbing in probably the most unhospitable and hostile environment on earth. i've nothing but the utmost respect for all of them. oh, and they don't dope..
Most of them take oxygen...That´s a kind of doping.It is a broad selection of people who go there.There are the "Everest tourists" who are on a egotrip and pay to almost get carried to the summit...And then there are the "Real" climbers.But they are´nt all Reinhold Messner´s that´s for sure.Everest has turned into a dump littered with corpses,oxygen bottles,tents and other discarded stuff...Sad really.
not all of them use oxygen. those who mean businness don't. i've met personally many climbers, just to name Kinga Baranowska (6 or 7 summits above 8000m, all without oxygen) or Adam Bielecki (climbed K2 during winter - without oxygen too). these are some of the greatest people i 'know', with an attitude like no other 'regular' athletes, and with some spectacular, nearly one-off achievements. nevertheless, my personal take on oxygen is that at ~8000m it's more like having a rain jacket on a chilly autumn day or riding on somebody's wheel in heavy winds. most pro climbers stay away from it (or try to), but sometimes it's a question of survival or finaling an expedition with completing an ascent - if you sit in a camp at few thousand meters for a month and have a one- or max two- day window to attack the summit, i believe it's justified to use such aid. bear in mind there are lifes at stake here.
it's a different story with the Everest though, as it became a sort of McDonald of Himalaya like you say. frankly speaking, it's a lost cause for pro climbers, as it's too overcrowded which makes it impossible to climb without oxygen - you'd simply die at your way back, having to wait even few hours to pass some critical points. i'd argue with the term 'carried to the top' though - you still need to be really something to climb all the way up and down alive. most of the victims die due to exhaustion after
reaching the summit. climbing in Himalaya, no matter the weather or skills, is pretty much about coming down safely, as the recent expedition to Broad Peak showed.