Virgin Galactic and SpaceX are two different companies. Virgin Galactic intentions is space tourism, still flying ballistically within the earths atmosphere. SpaceX is a serious space engineering company capable to send satallites into LEO, as well as cargo and humans to the ISS. That's why NASA has made a contract with SpaceX of 1.6 billion USD. The most sucessful company currently is Arianespace by the way, with more than 1 billion USD revenue per year. I guess everyone knows their Ariane 5 rocket operated by ESA (yes it's commercial and it works). In thise league (SpaceX and Arianespace), Virgin Galactic does not play any role at all, nor is it comparable. It's like trying to compare apples and pears. Commercial does not stand for tourism or non-governmental funded. It's just a different method to distribute money for serious space flight engineering.
As for the Space Shuttle: the Space Shuttle requires a huge and expensive infrastructure which only NASA has. There is no company which has such an infrastructure (consisting of several companies, space centers and facilities), the required know how and most importantly the required money to operate something like the Space Shuttle. The launch cost is ~1.5 billion USD. But most importantly there is no rational reason at all, neither for NASA nor for somebody else, to operate the Shuttle any further just for the sake of some fan-boys (which I am as well) to see it continue to fly and be happy. The reason for the Shuttle retirement beside aging is its risky design flaw and the massive costs. The only reason the Shuttle survived after STS-107 is NASA's commitment to use it for ISS assembly. Without the ISS in Orbit, STS-107 would have been the last flight of the STS program. Whilst with potential issues during the last Hubble servicing mission, that would have been the end as well even in case the ISS would not have been finished, as had been pointed out by the managers. The Shuttle operates on its final breaths technologially and costly. Not even Roscosmos would be interested to operate that money hungry brick.
As for China: the whole Chinese space program gets totally overestimated. Their program is not in a good shape (only 3 manned flights within nearly a decade and "0" science whilst they intend to fly into space manned for more than 4 decades already). China does not get any help. China is not an evil communist country that tries to be the king of the universe. There seems to be some mistaken enemy images by some people these days. China can be lucky if they manage to get more experience in space anytime in the future.
The leaders in space are, and will continue to be: NASA, ESA, and Roscosmos (and its smaller partners around the globe). They'll work together like they already do, and more commercial companies (beside Arianespace) will join.
