I'm not excluding the occasional travel and am very much enjoying it and trying new things. What I am questioning is the extreme prevalence of travel in off-time for some people for whom travel seems to be the only way to spend holidays.
More poetically (but probably a bit patronizing, thus my original post which instead asks questions): traveling is cool, and staying at home is fine too. Next time you're planning holidays, what if you gave yourself the chance to appreciate your surroundings in a way you're not necessarily doing while in your regular job routine? You don't have to board a plane to see new things. Chill out. Meditate or try to build something if that's your kick. Go have a walk around the neighborhood. Take your time.
For myself, it's simply that vacation days are too scarce to waste on anything I could feasibly do during the evening or on weekends. It might be nice to take time off for the activities you mentioned, but it's not essential, I could do them at the weekend. Each year I have 240 working, 100 weekend, 10 public holidays and 15 vacation days. I have some "required travel" that uses vacation days too (e.g. I'm taking three days off next week to go to a friend's wedding and visit family), so I make sure I maximise my "pure travel" with the remaining days.
I can easily see this in the United States, since any public transportation beyond the local level is so expensive it's a luxury for a big chunk of the population, and the distances between interesting places tend to be a lot bigger. For example, I could spend a couple of hundred dollars and take the train to the nearest other "big" city, but it would be a three hour ride and there's nothing to do there except go to the mall and watch a movie, or drink in a sports bar with a bunch of strangers. It's harder for me to imagine someone growing up literally anywhere in Western Europe and never traveling.