I say "lifetime dream" because, within that context, $50,000 is probably a good, achievable budget for the lifetime dream of probably north of a billion people in the world. Maybe two billion; I haven't looked at world demographics lately.
$50,000 is enough to do any one of starting a small business, or owning a classic car, or getting a masters degree in a subject you enjoy, or to own a boat or a tiny prop plane, or take a year or two off to try to write the next great novel, or buy a small plot of land in the wilderness to put a cabin on, or take a pretty fantastic round-the-world trip, or serve as a down payment on a small house in much of the US, maybe a fixer-upper depending on your location, or to throw a really amazing wedding. Or to climb Mount Everest.
Any one; if you aren't a rich asshole, you only get to pick one (or if you're a rich SWE, like 4-5). But, like, a lot of people can scrimp and save and take out a second mortgage and do one.
I understand why you think wanting to climb Mount Everest is a stupid dream, and I'm sure that a hearty number of the climbers are rich assholes who don't bat an eye at dropping $50k on something they don't really care about. And heck, most of the people who do dream of climbing Everest aren't in the physical shape to actually go and do it.
But still, it's a pretty common dream of a lifetime, of the right scale that a huge number of people are able to attempt it.