Well said.Exactly true. There are still plenty of use cases where desktop computers are necessary and touch interfaces are pure torture. And this is not likely to change in the next decade or two. Programming, development, 3d design, graphic design, digital art, music/sound editing, video editing, etc... the list goes on.
Tablets and smartphones are nice for the things they are used for, but the idea that they could replace all computers is idiotic. Touch interfaces do not scale well beyond about 12", above that they are horrible ergonomically. Touchscreen keyboards will never be as ergonomic as real keyboards, and touch input is less ergonomic than using a mouse, so any work that requires long periods of interacting with an interface will require a) a big enough screen and b) keyboard + mouse.
One could argue that we might get tablets that are powerful enough that if you attach a monitor, keyboard and mouse they could act as desktop computers. But why would we need tablets for that? What benefit could there be to combine two devices of very different purposes into one? That's the dock thing all over again, the reality is it's much easier to have a separate desktop computer and tablet.