Actually, an adjustable tilt screen can be quite expensive to make. You have to remember that for those arrangers with touch screens, the screen has to lock securely enough that it will not move while you poke and prod it (fairly firmly), or in non-touch versions, the buttons that surround the screen (and are critical to selecting what's on the screen) also need to be very firmly fixed.

You also have to take into account that the displays like the KN1000, only a 2 line LCD display moved. No buttons moved, no touch-screen needed to be braced. A VERY different proposition to today's huge displays.

I have not yet played a PA3XPro, only the non-moving PA3X61. But I imagine that that motorized, moving display adds considerably to the cost of the arranger. Maybe not a big deal on a $3500+ arranger. But likely quite an addition to a $1500 one.