It's just unfortunate for both of them - they put up truly insane stats that break all sorts of records, but then they have to beat *each other* in the race to post even more ridiculous numbers. The title of 'best player in the world' has basically become a sort of baton they pass between each other, and each will likely always be talked about with heavy caveats necessitated by the presence of the other, even long after they retire. Whereas in a less competitive age where only one of them was active at any given time, they would each be the undisputed kings of their respective playing careers.
I agree, though - ultimately, there are eleven men or women facing up against eleven others on any football pitch, not just the one against the rest. So it's less about the 'best' in this sport than it is in others, even as recognizing individual talent still plays a big part in football as a whole. And, now that they're both reaching the twilight of their careers, maybe we'll see an undisputed 'best' emerge again - or, alternately, see several players compete for that title.