Given that Firewire 400 gives more throughput than USB 480, some 15-70% faster (depending on the test), I'm betting the performance between the two will be close. Then the question is what the other advantages are. USB has only one serious advantage -- it's less expensive.
A second advantage is the proliferation of existing products already using USB. For a manufacturer to upgrade to 3.0 from the current 2.0 spec would be cheaper than switching techs to firewire, I would think.
Intel doesn't need for USB to out-perform firewire -- it's already "good enough" for most applications, and as long as it stays pretty close to FW in speed, I think its position is fairly secure. But Firewire's not going anywhere, and the biggest reason is a niche market the author doesn't mention. It's how you get video out of a digital camcorder.
I live my Macs, but I have no illusions about Apples influence on standards -- Firewire won't go away, but that's due to Sony more than Apple.