Because if you launch something from Earth, you inherit the Earth’s orbital speed around the Sun. At that point, whatever you launched will just continue to orbit the Sun. It takes less energy to accelerate to a solar system exit trajectory than it does to scrub off all of the excess velocity and end up on a trajectory that intersects the Sun.

Most of the Falcon 9 launches are for Starlink and are paid for by SpaceX themselves. How is that “the government subsidizing them”? If you want to argue that they’re using money they got from NASA to fund those launches, is your plumber feeding their family from you subsidizing their life?