The reason I am not FIREd yet is that I'm saving enough to allow continuation of my current travel habits. Although there are endless worthwhile destinations in my own country, there is also something to be said for experiencing other cultures and seeing places that are simply nothing like anything we have in the US. So travel is worth it to me.
That said, I do travel fairly inexpensively. The expensive stuff seems to be stuff that's similar to home... the nice hotels, the meals at fancy restaurants, etc. I actually prefer to stay in a locally-owned inn or AirBnB, and experiencing the food culture is probably best done by eating at markets and street stalls. As mentioned above, nature is usually free, and I do a lot of hiking, etc. I have paid for a guided hike in places like Iceland's Westfjords, where the weather can go instantly from sunny and 70s to blizzard and the trails are not necessarily idiot-proof -- or Italy's Amalfi coast, where even the guide got a bit lost. Still, that's cheaper (and more fun, in my opinion) than a flashy hotel. In general, the way locals do things tends to be not only cheaper but more authentic -- the street food, the "chicken bus," and the particular activities they choose to partake in, like $8 massages in Thailand.
I also enjoy poking around grocery stores to see what they have and getting my own food for at least breakfast and lunch. I don't see this as "I'm too poor to have a real meal out." I see it as a fun opportunity to explore a culture through its food. As a bonus, I've heard that carrying your wallet, camera, etc. in a local grocery bag can make you less prone to crime. You might still stand out as "not from around here," but at least you've been around long enough to require groceries, and you're "poor" enough to shop like the locals.
Yes! Cities ARE pretty much all the same! It's interesting enough and cheap enough to stroll around a bit and maybe pop in somewhere for a cup of coffee and an hour of people-watching, but beyond that, I just don't really have any interest in cities.