First, go to this page and download the Test Drive Rules 4.0, basically a free PDF that is pretty much the entire ruleset right there, including character creation. The main things that are missing are more special case rules.
http://www.peginc.com/Games/Savage%20Worlds/Savage%20Worlds.htmSavage Worlds is basically 1 book with just rules. As a warning, they're based off miniature wargame rules, which is partially why they're so fast, so some things it does will seem odd to a pure role player. They're also somewhat geared for more heroic action adventure games right out of the book, but tweaking is not only encouraged in the rules it's also the norm for the setting books.
The publisher has gone on record saying that they won't be printing fifty books for the same setting and making their settings too unweildy to use. You'll need just the main rulebook, a setting book (or a setting of your own) and maybe an optional side book or pdf adventure.
The key reason why it's so fast, at least for the GM, is that everything's rated the same way. Just 5 attributes and a set of skills that are rated in about 5 steps. It's really easy to think up an entire stat line, and the stat lines take up about a paragraph instead of an entire page that D&D does.
As for the topic, the reasons why things are more popular are pretty simple and we've already covered most of them. It's just a sign of the times too, with everything being so fast paced nowadays. It's just easier to fire of a cooperative video game than to setup an RPG session. That said, who knows what the future will bring. Maybe a full VR system and thinking computers will help role playing come back big time with fully interactive GMed VR campaigns. But it's somewhat doubtful it'll still be called role playing.