Ben Lovejoy opines on 9to5Mac:
A fast, clever technology developed by Intel and enthusiastically marketed by Apple ought to stand a fighting chance at mass-market adoption. Sadly, there’s so far not much sign of this happening. It’s all looking rather reminiscent of Firewire…
(The ellipsis is his, by the way.)
I think it is destined to have a similar adoption strategy as Firewire, insomuch as it’s a connector designed for niche use cases. Thunderbolt is not designed to replicate USB; USB 3 may have fast transfer speeds, but it’s nowhere near as speedy as Thunderbolt. Combine that with the variable-speed implementation of USB and you have a recipe for a peripheral connector that works well for the mass market, but is poor for those who need fast, consistent speeds in both directions.
Lovejoy trips on that here:
But we all know that technological superiority is no guarantee of commercial success. The mass-market went with USB. Partly because consumers buy numbers without necessarily knowing what they mean, but mostly because it was cheaper. […]
Intel intended it to be the new USB. Optical thunderbolt was supposed to take over from copper, and there was supposed to be a Thunderbolt port in every PC. Neither has happened.
Thunderbolt was never designed to be a mass-market standard in the way USB is. USB works extremely well for connecting devices which require low power, are simply transferring data (not an audio or video signal, for instance), and aren’t dependent on constant transfer speeds.
Thunderbolt is also based on PCI Express, which means that Intel couldn’t have intended for it to replace USB. Aside from some hard drives, USB peripherals typically aren’t based on PCIe, and adding it isn’t a trivial matter.
Thunderbolt is an expensive connector standard, but it’s the very best. It doesn’t need to be cheap because it’s not for your smartphone or SD card reader. By putting it in every new MacBook and the iMac, Apple is ensuring that more people are exposed to it, generating a higher likelihood of third parties producing peripherals. They seem confident enough in this strategy to make the new Mac Pro a central hub to which users can add a series of peripherals designed for their line of work.