Actually, we aren't spending any taxes on launch vehicle R&D. NASA spends all $13 billion it receives from taxpayers on orbiting politically-correct mission specialists to monitor ant farms of elementary school kids.
The space shuttle, NASA's last grand space launch vehicle to be developed, is twice as expensive to operate as the launch vehicles it was supposed to replace.
No new launch vehicle design has been prototyped, produced, and put into orbit since 1973, when the Space Shuttle design was finalized. This, despite NASA spending approximately $300 billion in public funds over that period.
When NASA took over the privately-developed DC-X vehicle developed by McDonnell-Douglas, it promptly crashed it on the first flight. Then McDonnell-Douglas was forced to blame itself for the crash -- lest it lose favor with NASA.
Because of the powerful political interests that have developed around the taxpayer funding spent on Shuttle, there will be no public development of an inexpensive launch vehicle system to compete with Shuttle.
Maybe the libertarians are wrong, but they haven't stolen $300 billion from taxpayers pockets and killed fourteen astronauts and acted defensive about it. This is why I like libertarians more than I like bureaucrats.