I really don't know why this got modded insightful. You're right that manufacturing capacity is a factor in military strength, but it's far from being the only (or overriding) metric. First, I'll address the logical failures in your post, then I'll respond to the rest:
They are here one day and blow to bits the next...All of these high-tech weapons are nothing but a flash in the pan if they cannot be replaced at the pace at which they are consumed, or faster.
Just like thermite's nothing but a flash in the pan. But if you have enough thermite you can still melt the fucking pan. Weapons do *not* need to be replaced at the pace they are consumed. They need to be available in sufficient quantities for the duration of the conflict. Come January 2005, the USAF was running low on several types of munitions. Did that help Saddam? No.
Bleeding edge, billion dollar bombers are worthless if there's no fuel to get them into the air. (and other irrelevancies)
Who are you implying lacks sufficient quantities of bullets or jet fuel? Certainly not the US... few countries can match the United States' ability to supply itself with petroleum and related products. In a truly massive conflict, strategic reserves might be depleted and the US might be forced to drastically ration... but remember that the US has the ability to take down one of the world's most feared militaries without mobilizing significant additional assets.
Now tell me, who has the largest and most rapidly expanding manufacturing and logistics capability in the world? It sure as hell isn't the US. Take a random sample of the objects presently surrounding you and look at their "made in" label. Notice a theme? What oil field does your fuel come from? There are strong odds against it being Texas.
China is great at producing consumer goods, but their military production is still second rate. They have poor quality control, numerous production issues, and, to put it mildly, their designs lack ingenuity. If they can overcome all other challenges, they might become a global military power someday. At the moment, however, they're struggling to keep up. And not just in technology.
Their expanding manufacturing and logistics are impressive, but they don't currently have significant global force projection. They lack the logistics to deploy a 200k+ man military, forward deploy large numbers of bombers, fighters, transports, refuelers, etc. Their navy is largely brown water and would be unable to deliver their army. They don't have a global network of bases that can be used to project force, and are unlikely to be permitted one. They are catching up in satellites and anti-space, but they have a ways to go.
Economics: Militaries stop being competitive when their countries can no longer sustain sufficient funding. While the US will undoubtedly be forced to reduce military spending, intelligent cuts (and revenue increases) could allow it to maintain global force projection and dominance for decades with a balanced budget. China is facing much more severe economic challenges and faces a real possibility of collapse should it fail. China has not begun to pay the much higher costs associated with a global military. They have modernized some, but they don't appear able or willing to pay what they would need to to compete globally. They are, however, a regional concern... with many other strong regional powers already acting to counter them.
In short: China makes nice phones, but they can't wage a war on a different continent. The US still has enormous capacity and can easily fight multiple wars on multiple continents. Barring a US civil war, this is likely to continue for at least another two decades.