Let me give you a hint as to why this is done. It is an old method but one used successfully. It isn't that private companies may not be able to do this or not, it is that the success rate may not be as high. Virgin is testimony of being a more successful entity than SpaceX is due to the fact it is more "private" than spaceX. Simply put, SpaceX needs the help in order to create a "superstar" be successful. In this case, Elon Musk. Like Zuckerburg, Elon Musk is paraded around as a genius whom only was able to make his dream come true (and a billionaire on top of that) by living in America! What they don't like to talk about, regardless how one or the there points it out, they are frauds. But it isn't the fact they are frauds, it is that they are an image - a portrait for others, to give this impression that the American dream is alive and well, and to create this kind of cult around the idea that if it isn't America, it is nothing. The American dream is dead, and has been since Reagan's Voodoo economics. So in order to keep this charade going, they create visionaries and illusions, with massive financial and technological help from the state, to give this impression on the rest of the world. Doesn't matter if it is successful in the book keepings. What matters is if it will keep the masses in awe and wonder, thinking that everything is grand and they must buy the new iPhone 12GS/FLQ/LGBT model. Reality is very different, at least in what we know of. In the background, US lives off of borrowed technology, people, money and time. Reality is, it is bread and circus. Funny enough, nation like Russia that invented a lot of technologies used now, and even made discoveries, believes they are "backwards" in technology, without even knowing that their tech is used in our Radar. Or at least have been since 1990's from Czechoslovakia. Little do they know that it was MCST that designed the multicore processors, little do they know of laser technology they invented is used in most disk reading tech, etc etc etc. But this illusions is what helped eventually bring the downfall of the Soviet Union. This illusion of Hollywood, Superstar geniuses, "Artists", grandeur is what keeps people thinking everything they do is the end all be all. Even a huge part of the forums community, whom likes to think they are most knowledgeable in knowing the "truth" of how evil the US is, still fall victim to these same fake grandeur. KVS has a lot of knowledge on the tech side of things because of his background. I have a lot of knowledge in it not because of my background in what I do as a job, but because of the people I know and the various situations my family has had to endure over the years. It is all experience. I myself as an example trust Militarov on various technology knowledge because of his job and experience, and when it comes to air defense systems because of his experience from the Serbian military. I was just lucky enough to have politicians and people working for the MiC in the right era, to be able to provide me knowledge.
We "Had" companies where I am from that built mostly for the navy. Then contracted out the military technology to private sector to make additional funds since at one time, the MiC was limited on their profit margin so they needed to increase their profits some other way.