OK, last, I'm sort of surprised you'd say: "Keep in mind that there is no faster navigation than with the finger. I'm quite sure everyone would agree with that."
I just don't think you've given this a lot of thought, really...
Quick example of many possible examples disproving your hypothesis:
You are sitting at a desk in a chair facing your 27" (measured diagonally) computer monitor; In front of you, of course, is your keyboard and mouse. Pretend that the task before you is a very simple UI task, that is, you have to activate an icon at the bottom left corner of your monitor, and then activate an icon at the top right-hand corner of your monitor touchscreen.
Touchscreen: I click on the bottom left corner icon with my right index finger, then I move my entire arm the full 27 inches diagonally so that I can click the icon in the top right-hand corner of my screen, also with my right index finger.
Mouse: (assuming the mouse cursor is mid-screen when I begin) I rest my palm on the mouse and rotate only my wrist perhaps 1/2 of an inch to move the cursor over the bottom left-hand icon and then left-click the LMB with my right index finger; I then rotate my right wrist approximately 3/4 of an inch so that the cursor is now positioned over the top right-hand corner icon, and then simply press the LMB with my right index finger to also activate the second icon in the exercise.
With the touchscreen I have to move my entire arm 27" to press both icons; with the mouse I merely have to rotate my wrist a total of maybe 1.5 inches and click on the LMB twice to accomplish the identical goal. Winner, ease of use and speed: mouse, hands down. Now, think about moving your arm all around that 27" touch screen to press on screen icons all day long while doing a variety of tasks, versus rotating your wrist slightly and left-clicking when needed to accomplish the same things. The winner again is the mouse by a wide margin.
Next, suppose the area required for activation is only a few pixels wide? The fingertip will prove to be fairly crude in precision compared to a high-resolution mouse (high dpi accuracy.)
Next, what about general cleanliness comparing a screen you've been touching all day with your fingers versus a screen you haven't touched even once for the entire day? WHich do you think will require more cleaning and hygiene?
Finally, HippsieG, know that I certainly respect your preferences and this post isn't meant to persuade you of anything--it's only meant to illustrate why *I* prefer the mouse & keyboard to a touchscreen-driven gui...