ehhh, sort of right but not.
Analogy time here.
6 of cars need to get down a 6 lane freeway, no issues there as each has their own lane. You can have 6 cars moving down the freeway per second.
But if 12 cars had to go down, you run into issues as you need to put 2 cars in a lane, which slows it down to 3 cars per second (Doesnt make much sense using cars and freeways, but that's how it works with computers).
USB3 over USB2 is equivalent to having more lanes on the freeway, not necessarily faster cars.
It allows faster speeds to be achieved due to the greater bandwidth, but if a device doesn't use that bandwidth, there will be no performance difference between USB2 and 3.