And it is REALLY close. Problem is, that there is a feat to increase the Greatsword damage, on top of the charger feat which can be used by all fighters, or you could go polearm and get those two feats plus Polearm mastery... and the Dual-Wielding fighter just doesn't have anything comparable, other than getting Charger like the other fighters.
The Dual Wielding feat with TWF fighting style lets you do 4d12 +20 --> 46 per turn at 11th level dual wielding lances.
When you consider the penalty to attack rolls, that is going to come pretty darn close to a GWM-PAM build or SS-XBE build and you are going to do it with a higher AC and only 1 feat.
In terms of white room raw numbers that is one of the most effective DPR builds. I don't think people like the thematics around it though.