The closest responsive touch screen you can buy today is a 27" Wacom Cintiq, which is $2,299 without a computer, and both lower-resolution (2560x1440 vs 4500x3000) and smaller (27" vs 28") than the Surface Studio.
So if you assume that about $2,300 of the device's costs go to the display and touch screen, you're paying ~$700 for the actual machine driving that display, which isn't a great value, but isn't bad at all.
A terrible value for people who aren't interested in the display, but not bad for people who are.