I believe the main reason is that many years ago Apple (which developed Firewire) demanded a royalty for it, on a per use basis, which Intel and the computer motherboard manufacturers considered to be excessive. Therefore Intel designed USB capability into its chipsets, and the rest is history.
Although Firewire continues to be extensively used in some applications, video editing being one example.
Regards,
-- Al
Although Firewire continues to be extensively used in some applications, video editing being one example.
Regards,
-- Al