Now for a second let's let you be the controller serving the busiest airport in the world (presently) Let's say you issue 3000 clearances a day on your 4.5-5 hours actually plugged in, ranging from climb and maintain one four thousand to turn left heading one eight five to contact tower one one niner point one, to intricate specifically timed approach clearances so as to seemlessly be able to go to the other 5 moves you've already made in your head. Now imagine having to say readback correct 3000 extra times. It adds a boatload of extra work, freq congestion and would ultimately cause delays.
That's why we only correct you when your readback is wrong.....it happens a LOT less times than you being right.