Why is traveling such a big deal for people?

Disclosure: I've traveled and I've lived abroad in two different countries and been dozens of places outside of my 'home'. But I don't get this…

When air travel became available, it was super expensive, which meant that only rich people could do it. About a century later, it became cheap enough that middle-class people could travel occasionally. Because of that history, travelling got a shimmering magic aura in our minds.
I live 20 minutes from the French and the Swiss borders. When I visit Basel or Straßburg I’m not “being like rich people”.
Attitudes have changed a bit since short distance flights aren’t prohibitively expensive any more. However, that’s still a bit of an exception. To many “air travel” refers to flying to a tourist destination once a year instead of attending a quarterly business meeting.
It’s worth travelling to Straßburg just for the melty cheese goodness.
I’m not anti-travel and I’ve enjoyed it in the past but I honestly think you pretty much nailed it. People try really hard to convince themselves that, actually, they’re not engaging in conspicuous consumption but instead growing as a person or whatever.
Travel has many facets, and growing, learning, and broadening your horizons are certainly part of it. Those reasons aren’t fake, but I’d argue none of them are the core reason why people think so highly of travel. Naturally, travel often involves conspicuous consumption, spending lots of money, polluting the environment, and general decadence. That’s why people feel the need to justify it—that’s why you hear so much about the secondary reasons.