I very much would like to see DC's marketing strategy for those years.
On the one hand, the reboot was supposed to bring in readers, new or lapsed, and since those people weren't reading Superman in the first place, distancing the product from what came before does make a degree of sense. If you weren't reading Superman pre-Flashpoint, being told that the "new guy" was rougher and edgier and whatever other lies DC told might have gotten your attention in a way that "it's the same guy, but we're starting the story over" wouldn't.
But like with so many other things, DC's inability to go "middle of the road" and their knee-jerk reactionism and sensationalism succeeded only in making established fans angry, and the lack of consistency (or any kind of planning at all) didnt provide a quality product to keep the new people around long term, and in the end we were left with sale figures equal to the end of post-Crisis anyway.
I'd love to see what DC's marketing budget and strategies are. I'm no expert but I do have a good eye for advertising and I'd love to take that budget and spin something worthwhile out of it. Give me a call, DC, I'll sell some damn comics for you!