You don't have to buy it and welcomed to believe what you want.
I'm not laughing at you, but laughing at how you actually think this is something impossible.
Just because you can't (yet) doesn't mean there aren't a lot of people who can. It's actually not hard if you're acclimated and actually train, and well within the capabilities of most people if they'd put in time. You're not getting there in a year, but it's not even close to being some phenomenal feat. I'm one of the slower people in my group of friends and none of them are anywhere close to being competitive at races.
If you were down here in Southern California and frequent San Jacinto's Skyline Ridge during the busier seasons, you'd see how many people can cruise up +8k ft on Skyline in the 2-3 hour range and it's a lot steeper than the sidewalk on Whitney.