You have got to be kidding.
The majority of new retail PC motherboards now have USB 3, even some atom boards are getting USB 3. USB 3 peripherals are everywhere at the local department store, especially for portable drives. Have a look on ebay.
USB 3 is also cheap. I bought a USB 3 pcie card for $25 a little while back and an enclosure for $20.
I can't even find any thunderbolt upgrade cards (pcie) or peripherals.
I disagree. Just because it hasn't previously been integrated into chipsets doesn't mean its not successful.
In the consumer world, pretty much. FW800 enabled hard drive cases remained extremely expensive. FW800 flash drives never really appeared, likewise with most of USB's other peripherals.
I didn't say it wasn't successful, I just said it hasn't "taken off".
In the future, Thunderbolt is going to be used for high-end professional equipment as well as docks, and USB 3.0 will be for your usual consumer devices. They will complement each other.