Why wouldn't the Chinese and the Russians sell Iran weapons for hard cash?? Those two countries are not too bothered by the American sanctions. It was Iran which was relying on its proxy militias next to Israel and its missiles as the strategic deterrence and so Iran didn't much invest in airforce or even much in air defense system. And the proxies were not a bad investment for a long time and neither was the investment in the missiles targeting Israel. But, we know, 6-8 months ago, the tide turned on the proxies and here we are.