You're "competing" against and playing with those within your geography though.It's an issue for those that want to be posting impressive screenshots on reddit/forums that live in the suburbs sure but outside of that minority most people are interacting with players that have similar opportunities to them.
That's basically how it is with the game's predecessor, Ingress. I'm lucky to live in an area dense with portals within a short drive. Some areas we've played in were so sparse there was no point in trying to capture, link, and field it.
Although, length of link and area of field got you more points, so there was some inducement to find open or poorly defended portals that are off the beaten path, in hopes of holding a large field. Portals at mountain summits and the like are often hotly contested. Of course you still have to be in the general area, but there is absolutely no point to venturing to out of the way gyms in POGo.
For the hardcore players with money to burn on traveling, sure. There was a player in our area who booked a flight to Hawaii literally just to field over the western half of the continent. There's also the risk/reward of holding an out of the way Guardian portal, even though it's easy to achieve that badge with a local portal too.
I don't think the creators of the game envisioned that kind of dedication, though. And you're right, that is a fundamental difference between Pokemon GO (which despite the claims of its older players, is definitely targeted at teens and children) and Ingress.
