17 million green cards rejected in 2023 alone might be one of the reasons! 
You got a point. I wasn't even aware.They might or they will source it out from other manufacturers that will allow them to pay in whatever currency they want to. But I guess since their alliance with BRICS is at hand and has been vulgar, are they going to purchase it from any of those participating countries that are also into arms manufacturing?
Weapon system is not that you ditch your Chrysler and buy a Toyota. There is tooling, replacement parts, ammunition sizes, stocked and needed.
I think Saudi Arabia and much of the east had their experience with Russian weaponry. Going Chinese?
So far only a few countries were allowed to buy. one is Venezuela. (No money for medicines, but weaponry?)
https://chinapower.csis.org/china-global-arms-trade/