Because someone has to. Otherwise we're bound to this little rock forever. And bored billionaires are the only people with the money and will to do it right now. It's also the only way we'll develop better ways to get commercial payloads into orbit given the recent global obsession with austerity.
edited to add:
Storing a library in your pocket seemed impossible (or at least commercially unviable) a hundred years ago. No one would have given it a thought. It was just too far out there. How could you pack that much paper into a pocket? I know the limitations on space travel are grounded in sound science and will probably never be overcome. But I don't like the idea of accepting that we'll never find a way around it.
Just as fitting that much paper was an issue so is trying to fit that much propellant into an improved rocket. The number one limitation on real spaceflight (AKA past the moon) is power. Building an actual fusion reactor on earth would be worth more in therms of actually sending people to the ort cloud than all the private 'space flight' (aka yacht clubs) out there.
PS: I am mostly taking issue with sub orbital flights / amusement parks. If you want to feel weightless for a few minutes a trip on something like the comet comet is affordable for most people and few people bother.
We're a civilization with a wealth of brainpower and resources. We can send billionaires to moon parks and Jovian country clubs while working on fusion without compromise.
The billionaires aren't just goofing off in space. They're building launch systems, advancing materials science, bringing costs down, and inspiring future generations of engineers and scientists while having a blast.
edited to add:
Storing a library in your pocket seemed impossible (or at least commercially unviable) a hundred years ago. No one would have given it a thought. It was just too far out there. How could you pack that much paper into a pocket? I know the limitations on space travel are grounded in sound science and will probably never be overcome. But I don't like the idea of accepting that we'll never find a way around it.
"Because it's there" is good enough for now.