USB was slooooooow in comparison to SCSI or later FireWire, though, so that took a hardware generations to really catch on.

I think the network effect was more a question of who had tons of data: for example, all of the graphic design shops had Zip or Jazz drives because they needed to schlep client deliverables around so you could just assume they had the hardware. Most people weren’t generating that much data before digital cameras became common.