Since the USA's military-industrial-complex primarily functions as political patronage, and is only secondarily about maintaining empire, is it possible that the actual purchasing power of the Chinese military budget is fairly close to what the USA is getting out of their budget?

I can answer this!

https://www.twz.com/china-acquiring-new-weapons-five-times-faster-than-u-s-warns-top-official

As well as the sheer speed with which Beijing is able to acquire new weapons, Holt contends, the Chinese are also operating far more efficiently. “In purchasing power parity, they spend about one dollar to our 20 dollars to get to the same capability,” he told his audience. “We are going to lose if we can’t figure out how to drop the cost and increase the speed in our defense supply chains,” Holt added.

“We have no competing fighting chance against China in 15 to 20 years,” Chaillan told the FT. “Right now, it’s already a done deal; it is already over in my opinion.”

Words of Cameron G. Holt, major general, in charge of all aspects of contracting.