Many people on this thread mention the parallel between aviation progress in the first half of the 20th century and what is happening now with SpaceX, Virgin galactic, and so on.
The difference is essential though. In the beginning of the 20th century we simply did not know enough about fluid dynamics to make aerodynamic flight happen easily. This is still a tough field (turbulence, etc) however we have made huge progress. We can model it relatively well, we essentially know now how to simulate it, etc. The basic equations (Navier Stokes) have been known for a long time, and thank to a huge theoretical, computational and practical effort, we now have cheap, save, available, commercial flight for everyone.
In the case of space dynamics, things are actually fairly simple. We have known about minimum orbital speed, escape velocity, and so on since Newton. We've made measurable progress with chemical rocket engines since then 1950s, but the principles were known at the time. We know how much energy we need to expend to reach space. We know how to navigate space, We know how to do it.
We actually know that we *cannot* do it cheaply at present. What we need to reach a new level is a lot of basic research in materials to build space elevators, better ion drives, perhaps nuclear engines in the future. At the moment we cannot send humans effectively beyond low Earth orbit, and again, this is not cheap. It is not so much a question of entrepreneurship, it is a question of long-term, constant investments. As in several decades.