We know how to put people in space and have been doing so for over half a century - spaceship2 is not doing anything new. The comparison with very early engines and engine driven vehicles is really not appropriate. The largest problem is that it has been very expensive to put people in space. Does spaceship2 address that problem? (there is also a very real safety issue, but presumably that would get better if the volume of space travel increased).
Spaceship2 uses air launch, and a conventional but low delta-v rocket to do a parabolic flight. Air launch has been used on small rockets before but is very difficult for manned missions because of the enormous fuel weight required to get a manned craft into orbit. Spaceship2 doesn't address this issue because it doesn't attempt orbital speeds and so can be very light weight.
Spaceship2 does not need to deal with significant reentry heating so its high drag mode doesn't really apply to a "real" reentry.
So I don't see any clear use of the spaceship2 technologies to "real" space vehicles.
That said, it is somewhat mysterious why space is so expensive. The fuel costs are 1% of the total launch costs, it is is not a fundamental "energy is expensive" problem. Presumably the cost is related to the combination of very low volume production and very difficult design issues. It is possible that the spaceship2 program would be able to address some of those issues, but I have not seen any discussion of specifics.
"Space planes" seem about as practical as "air ships" and "flying cars".