I never reached a rating above 1000 and I was there 3000 years ago when the original gap was still played.
To cite the famous Morpheus:
"What is the Gap? Control."
FA is ultimately complex. You can be attacked from basically all directions, even water or mountains only protect you so far. Then there are so many ways of attacking v from plain unit rush, artillery bombardment, tactical/strategical missiles, strategic bombers, experimentales
Instead of rating I reached the wisdom that some people need to dumb down the game because the complexity is too high.
People put themselves into a very restricted environment, where there are less things possible (no sneaking behind base, easier turtleing,...).
Actually the modern dual gap is actually an improvement over the original gap. Instead of one central turtling point each team has its own. There is water available. And there is a skirmish area in the center to fight about.
So yes, maybe Dual Gap doesn't help you getting better. But it makes a lot of people happy, that wouldn't play FAF at all if we forced them into a different direction. So who are we to judge?