Whats the point of paying a premium for MTB clothing specifically designed for high-altitude riding when a set of carefully chosen, general-purpose mountain bike gear will suffice, especially for those who only occasionally venture into high-altitude terrain, and what specific features or technologies should one look for in high-altitude MTB clothing to justify the added cost, and is it really worth splurging on a set of high-altitude-specific gear when the difference is likely to be negligible for most riders, and are manufacturers just cashing in on the high-altitude trend, or is there actual science backing up the benefits of high-altitude-specific clothing, and can anyone name a reputable brand that actually puts their high-altitude gear through rigorous testing and provides real-world data to back up their claims, and whats the deal with all the hype surrounding high-altitude MTB clothing when most riders will never venture above 8,000 feet, and is the whole high-altitude clothing market just a case of Emperors new clothes, with manufacturers convincing riders that they need something they actually dont.