According to the link and reasonably assuming that the reference to commercial air travel implied human payloads, none of the technologies above readiness level 2 are suitable due to either lack of payload capacity or gee forces induced or both.
What the table shows is that it might be theoretically possible to develop some other technology, not that such a technology actually will come into existence.
Neither the short time horizon nor the human space travel restriction were in the original question. Nonhuman space delivery will become routine relatively quickly, and human space travel will become routine after. It's inevitable.
Yes, there are fundamental laws of physics that say we cannot make it routine. [1]
[1]: http://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation