"But what SpaceX are attempting to do has the potential (at very least) to bring about significant changes to the history of space travel."
I seriously doubt that. Lauching might become cheaper but thats all. Until a completely new type of space drive system is invented that doesn't rely on chucking mass backwards to move forwards humans won't be going much further than the moon again anytime soon. Even trips to mars are a pipe dream due to it being a one way trip.
All Henry Ford did was make automobiles cheaper. Clearly that had no real impact on the history of cars.
Once you get costs cheap enough, all sorts of unrealistic things become possible.
Why don't families go to an orbital space station for a holiday? noon could afford it
Are there manufacturing processes that work better in micro-gravity? Yep, but none are currently cost effective.
Why don't we mine asteroids instead of strip-mining earth? it is cheaper to mine on Earth.
If you make it cheap enough, space will no longer be the domain of governments and the rich, but something everyone can make use of, and there is no telling what people will come up with.
Also, the only reason Mars is currently a one-way-trip is because it is too expensive to launch the materials for a round trip.