Who can blame him at this point?
Usain Bolt barely even broke a sweat in Beijing this past year when he broke every Olympic record in front of him. The 100 meter world record wasn't even a challenge, as he celebrated for the last 10-15 meters, and he also took down Michael Johnson's 200 meter world record -- which had stood for 12 years.
Now he's going to start running the 400-meter, and there is very little doubt he can easily shatter this record as well -- also owned by Johnson. He's obviously the fastest man in the history of the planet, so I see no possible reason he cannot break this record with ease, barring injury.
In fact, I started doing some thinking about Bolt and his amazing gift. Remember those Man vs. Beast shows on Fox? When they did sprints, they'd pit a sprinter against a giraffe or zebra or something. The human would always burst out of the gate with a lead. Once the animal got a little warmed up and started moving they'd blow by the poor human with ease.
If we set this up between Bolt and a zebra in a 100-meter dash, I'm quite confident he could reach the finish line before the zebra blew by him. I mean, did you watch him run the 100 in the Olympics? That was a joke. He wasn't even trying, so let's give him a worthy adversary in the form of an animal. Maybe even eventually a gazelle or cheetah would line up next to him, just so we can see that he's human and capable of losing.
On a serious note, Bolt would be the first man to ever own the world record in the 100, 200, and 400 at the same time. It would be quite the historic feat for a transcendent sprinter. It's a no-brainer for him to make this leap as he looks to capitalize on his window of opportunity.