This is because private ownership stimulates innovation.
It's not clear what you are trying to say here. You start with a false premise, the old canard about the Japanese not being able to invent anything (the second-largest holder of U.S. patents is a Japanese company, Canon).
From there you proceed to tell us that the advantage we have over these other guys is the idea of private property. What on Earth makes you believe that the concept of private property is unique to the U.S.? The Japanese had a whole generation of entrepreneurs (Honda, Matsuda at Mazda, Akio Morita at Sony, etc.) who followed trajectories very similar to those of Henry Ford or David Sarnoff. All built very large private corporations and became fabulously wealthy men, just as any successful entrepreneur here would.
There's nothing wrong with a little rah-rah, but lying to ourselves about our competitors having weaknesses that they don't have is the first step toward getting complacent and losing to them. The compact disk was invented by Sony and Philips; the DVD by a British company. We certainly have our share of ideas, but let's not kid ourselves: ideas can happen anywhere.
"Cannot invent aything" is a strong statement. You made it; I did not. Yes it is an old fact that the Japanese have perfected the already existing ideas, and that in itself requires innovation. That innovation was marginal (and a lot of marginal increments can produce a large, even infinite integral, as you know), and you cannot possibly compare any of their corporations to our automobile or aviation in their respective infancies.
As to the private property, again, I did not say that it is unique to the U.S. -- you assumed that. The ease of business formation is still unparalleled in the U.S.
What also had in mind is that, placed in the public domain, the servicing of a product acquires feature of a public good. I do not think that, say, N years out, the provision of support for it will not fizzle. I have more confidence that a private good will be provided by the market.