You're not wrong from a Pareto frontier standpoint. It's certainly the case that many western travelers are engaging in what can pejoratively be called lifestyle consumerism. But I'd caution you against throwing out the baby with the bathwater. And in fact, I'd urge you to look backwards in history to see evidence of the value of this kind of cultural exchange.
Cultural exchange is not a one time thing, but an ongoing process. Perhaps someone goes to Europe for utterly superficial reasons a couple of times and enjoys it. But maybe the next time they do it, they seek to actually set roots in and assimilate into the culture. Nobody really knows when or where the conversion point is; it's somewhat unique and up to the individual. I'll give you an example from my personal experience -- I didn't really get the hubbub and the point of "traveling to Europe" and had skeptically discarded it as something that Americans do in order to pass off a feeling of vague superiority and worldliness.
Even so, it was very challenging for my gruff preconceptions to last very long when I spent a few weeks in Lisbon. My friend and I met some amazing local folks who showed us the Portugal we wouldn't see on the tourist path. I was hooked. My eyes were opened to a "third path" between the grind and hustle of American culture, and the low key daze of bucolic village life. Hitting the dancefloors until 4am paired with spending beautiful afternoons on the waterfront, eating delicious seafood and walking until our feet hurt. It's true that we could do all of this in America, too. But it was just a lot more fun in Lisbon. My eyes were opened to the deep, rich history of cultural exchange with the Moors, and I never got tired of the architecture, the cuisine, and so on.
Had I "really" assimilated into the city? Well, not really. I didn't quite have the guts to go all in, but my friend did, and went on to spend the next 6 months there. And then we visited again next year. And maybe we'll buy property there at some point.
My point is that it's a little reductionist to reduce an extremely broad human interaction (traveling) into a fixed point. It's a beginning, not an end. Just because so many people never get past the beginning doesn't change the fact that much exists beyond it. Almost every major civilization and empire was born from trade routes that existed to serve this exact kind of exchange. Consider the greater Silk Road for one.
It's easy to become cynical about rampant consumerization and the dull, lifeless, almost suburban collapse of what could be such a rich experience into two dimensions and an instagram filter. But that is a loss on the part of the person who lives life that way. It doesn't reduce the potential of the experience itself.