So you're okay with cutting funding for NASA, and allowing SpaceX or any competing companies to take over? I don't necessarily disagree with that but...
Does SpaceX really care about safety? They are a corporation, and they will cut corners wherever possible to save money. As long as their butts are covered legally, they won't get in trouble for saving $10 for not replacing a broken seal which could lead to a loss of dozens of lives. NASA would probably not be willing to take that chance, simply because they are not trying to make a profit. Remember, that's basically what happened with the BP oil spill. They tried to cut back on their safety measures to save money (because Bush and friends let them), and look what happened.
Is space travel really profitable to begin with? I think it can be, considering the asteroid belt is rich in rare-earth minerals, which cost thousands of dollars per ounce. But what if it's not? Then, we won't have any sort of space program.
What if SpaceX monopolizes the industry somehow? This one is kind of a stretch, but I'm throwing it out there anyway.