Then we get blasted by a gamma ray burst from Betelgeuse and we're all dead. Studying the cosmos is extremely important, and studying threats (asteroids, supernovae, etc.) are just one part of that.
What is the point of studying the cosmos if we never leave our planet? Space is coming. Admittedly much slower than we expected. However SpaceX's satellites are just the beginning. Astronomy will continue, just much more so. Imagine a telescope array the size of the earth scanning the stars from orbit. Why look at an asteroid when you can GO there and do something with it?
