I've done 300,000 feet a lot of years and I'm not a great climber. Did 12,000 feet in a century type ride once and I still felt it a week later.
My friend does over 500,000 feet every year and he is not fast or a great climber, just dedicated.
Some people do 1 million feet in a year but have said it gets to be like a job and no longer is it fun.
Everesting, what a concept. Find a steep hill, 1 or 2 miles and do it 85 times. No, thank you.