I think it all comes down to motivation. If you really want to do something, you will work hard for it.
I like to think of Everest as a great mountaineering challenge, and when you've got people just streaming up the mountain - well, many of them are just climbing it to get their name in the paper, really.
The Sherpas play a very important role in most mountaineering expeditions, and in fact many of them lead along the ridges and up to the summit.
Tourism is a very big economic benefit to the Sherpa people, and also, they have very strong ties to their own social attitudes and their own religion, so fortunately, they're not too influenced by many of our Western attitudes.