That's an incorrect statement actually Synapse. Everyone in the older generations can understand quite a bit of Russian, but certainly not everyone. I can say this from personal experience, and I have many friends and family in Ex soviet countries, or the surrounding area.
Since the breakup of the soviet union, the younger generations learn English instead. I'm Lithuanian and Everyone above the age of 30 is fluent in Russian, almost nobody under the age of 20 speaks it well. But they're all fluent in English now instead.
Same applies to other countries, like I know when my Dad went to Bulgaria, he said he communicated with the older generations in Russian, but the younger generations in English. They knew absolutely no Russian at all pretty much.
While there are countries where Russian is still dominant such as Kazakhstan and Ukraine. For the most part, the younger generations in European countries at least are no longer speaking Russian. I can't speak for Asian affected soviet countries, I presume Russian is still somewhat more dominant there, but that's only my guess.