A more important part of the reason why Russia and China can develop these new systems is that they massively underfund the rest of their militaries.
Honestly, Russia and China play their cards a lot smarter than we do.
They use their money to develop very advanced weapons. They do not spend money on nation building and getting bogged down in guerilla warfare anymore; the Russians learned their lesson from Afghanistan.
And, as I mentioned, they certainly don't spend $1 trillion plus on social welfare every year as we do.
We no longer have the technical edge in advanced weapons. The Russians can do anything we can do, and often do it better. The Chinese get much of their technology from the Russians, and will soon be on par in their own design bureaus. The Russians are far more advanced than us in ABM systems, SAMs, ICBMs, and other areas.
We are becoming third rate due to the massive social welfare spending, and due to the fact we are spending our DOD $ on police action in foreign lands instead of keeping pace with Russia and China in advanced weapon design and procurement.
Yes, our best army division can out pound their best army division since we spend more in that area. But, we are starting to lose bigtime in advanced weapon design and procurement for the reasons mentioned above.