It all comes down to how many genius level engineers you have and how many dollars you have to spend.
We have lots of both...but do we have the will?
If we spend every spare dollar on social programs we will fall dangerously behind.
Russia, China, India and Israel all have the brain power and the money to create super weapons... just like we do.
None of those countries have the industrial base and budget the US has. Three of them have very large quantities of obsolete equipment, so replacing them eats up your budget. Israel has a relatively small budget, so its unfeasible for them to develop multiple types of cutting-edge equipment unless you are talking co-development.
“We have lots of both”
So do they and many of theirs are over here learning better manufacturing techniques. I have been shocked at how many Russians have had access to what I would consider national secrets.