The amount of light will still be appreciable and will affect many kinds of observatories around the world, even at magnitudes less brightness.
You also can't slew a telescope in space like you can on ground, it would be extremely cost prohibitive in terms of fuel.
"moving telescopes to space" is the equivalent of "let them eat cake" comment in this funding environment. It sounds like a wonderful proposition until you realize how many observatories we have on the ground and their utilization and how expensive it would be to replicate half that utilization. It's already not easy getting time on a telescope, if everybody had to be crammed on 15 space observatories costing $1B/each, there would be no observational time for grad students or post docs let alone funding for research. You also kill follow up observations on temporal events.
Of course, maybe the government could reach an agreement with SpaceX to send up the observatories for free and send some money the way of the astronomers for seriously messing up the sky, but there's no reason to expect SpaceX to be a good citizen of the night sky.
