10 times more expensive than USB 3.0
Taiwanese manufacturers are all about micro margins, they make small margins on their devices and as long as they sell enough of them, which they usually do, they can make a nice living.
Currently a USB 2.0 controller if you already don’t have one in chipset cost some 10 cents. This is definitely small change. A USB 3.0 host sells for 10 times more, or 1 USD. This is already a significant cost increase for board and notebook manufacturers.
If you want to add a sexy new Thunderbolt controller you need to send some 10 USD per device which makes it 10 times more expensive than the already quite fast USB 3.0.
Apple is the only company that has Thunderbolt on all of its latest notebooks and desktops, but we are sure that Apple gets some kind of special treatment. The price tag is the main reason why we are seeing very slow adoption of this rather promising technology.