Sounds like a good idea, except we have a hard time getting really large things off the ground. If you notice the size of the James Webb with its unfolding primary is still really small compared to other terrestrial based mirrors. It's mind boggling to look at the size of those mirrors, and then easily missed is the comparison to the former dish at Arecibo. Arecibo doesn't even fit in the image and is just an arc that looks like the background.