Was it? Or only since Bethesda decided that pre-war america was such a huge thing to highlight in the series? Point is, when you look at Fallout 1 and Fallout 2, how much of a role had the pre-war world of Fallout in the setting really? I would argue it was only miniscule, like the background, I don't think it was ever meant to be a focal point of the series. I also liked that most of the history in Fallout, was really just a mystery, ruins for the player to explore, if he so wished. But what made Fallout interesting for me, was the interaction with the NPCs and some of the factions. I would prefer a character like Lynette, the Khans or the NPCs in Navarro over 10 Nuka Cola explore-another-thing-of-the-past! scenarios.It's hardly that powerful.
Personally, I think the whole idea is quite fitting for the Fallout setting. Capitalism gone wild is an integral part of the series- and what screams Capitalism more then Coca-Cola?