I think the root cause for this is that Sony and Apple decided to demand a royalty for each firewire device.
Bernard is not an MF shooter or video guy so he doesn't care about firewire
Actually, Apple never charged to use the technology itself, and in fact made it freely and openly available as a published industry standard, IEEE1394. But strangely, Apple initially charged to use the name "Firewire", leading to the avoidance of that name. And apparently, the modest extra hardware cost, $5 or $10, on top of the USB that every computer needed anyway, was enough to limit the adoption and development of Firewire/IEEE1394 in the very price-sensitive world of mainstream Windows PC hardware.
P. S. there is however the sadly familiar issues that dozens of patent holders claim that the use of IEEE1394 infringes on various of their patents, so that an MPEG LA licencing pool is involved.