I hear calls for privatisation of organisations like NASA all the time, and I definitely understand (even support) the motivation for it. However, you need to understand the way these things work first, to understand the down-side of privatisation.
It's all about RISK. Many of the good programs that organisations like NASA are running are risky, in a financial sense. The idea of public funding in these cases (not the only reason for public funding, btw) is to spread the risk. When people claim that private industry can achieve the same things as NASA, they will often be wrong by default. This is because private industry will not accept the high risk of failure and conjectural returns of many blue-sky ideas, so they won't even consider investing in them. Industry is good at slow incremental progress (like iPhone 4 to iPhone 4s), but not so good at revolutionary progress. While many advances can be made incrementally, albeit more slowly, there are plenty of examples of non-incremental advances (like... the advent of microbiology, which wouldn't have followed in any incremental way from miasma theory without the input from optics).
So, you might ask: what are the benefits? I'm going to assume that you don't see scientific knowledge as an end in itself, and I assume that the one-off consumer products that we hear about don't excite you, so I'll restrict myself to a very specific, generic industrial method: Finite Element Analysis. FEA is something that was developed in universities alongside the earliest computers. Early FEA codes were specialised, sometimes buggy, and treated with scepticism by industry. Within NASA, these early codes began to be applied to certain problems, but NASA groups recognised the need for a more centralised, methodological approach. So, they threw some hard-earned-taxpayer-money at the problem (yes, YOUR money!) and NASTRAN was born: the first "industrial-strength", validated, quality FEA code set. Fast forward, and these days, FEA is considered both essential and central to a huge range of Engineering work: the design of everything from bridges to cars involves FEA in a key role. However, the vast majority of people who understand the history of FEA will acknowledge that we'd be far behind our current position without NASTRAN and the early NASA support. This is what public funding gets you: an acceptance of early risk and willingness to take on "blue sky" projects that may become central to industry within only a few decades. You just won't get that from private enterprise, even a "Kickstarter-driven" kind of private enterprise.