Hello,
Yep. In the real world, FireWire is faster than USB 2.0. Though, not greatly.
Cost and marketing are probably the two most significant factors which affect the popularity of both of the technologies. The marketing of USB has been more successful than FireWire. When FireWire technology was nearing the end of development, development of USB increased due to the threat of Apple contemplating on charging manufacturers a large sum of money per port to license the use of FireWire patents. As a result, Intel chose to implement support for USB in their chipset technology, and Intel was a big player in the market.
In addition, on a cost benefit analysis, USB costs less then FireWire to implement (and cost is important to manufacturers), and simpler than FireWire technology, while still providing good performance.