I think you also need to take in account that when it was truly a FEDAL era, that lasted for so many years, it was always Federer and Nadal in the spotlight. The media attention, the marketing, the merchandise, the sponsers etc. Nadal filled that Niche perfectly and enjoyed a very good reign at the top with Federer. Yes, their opposing styles added to the allure, but it was the constant exposure at the top...Federer and Nadal were simply the face of tennis. And then there were the others.
The other thing that helped Nadal was is incredible and ruthless domination of the clay, breaking record after record on that surface. That alone started opening up historical acheivements of the greats of the past, and Nadal's name grew even more. This had nothing to do with Federer, who was in the midst of making his own legacy, this was something that Nadal was just doing on his own. The King of Clay - That is a title that sells to fans around the world. It instills a sense of royality on the player who holds it.
And lets face it, everybody loves a winner. Nadal kept winning and winning and winning, smashing numerous records, opening up debates that had been long settled, or joined current debates.
Djokovic really truly rose to prominance in 2011, and yes, despite him not being anywhere the Fedal era giants, has seen his popularity soar greatly. Many more people now know who he is. 2011 did so much for his career, it really gave him the adrenaline shot he needed to break away from under the shadows, and create his own name and legacy. He probably will never reach their levels, since most of the fans over the years have been invested more emotionally in Federer and Nadal, since they were the top guys for so long. But ife keeps staying strong, fighting hard...And this is the one thing that Novak has over the others in my opinion. His ability to unleash on MPs, that alone makes people think about Djokovic more than other players. He's making a name, but it will take a bit more time and hardwork...but I think his time to do it is now.
Society is breeding a new kind of troll...But this is where the trolling stops...and I start.