There are leaks from Russia though, like when their entire Olympic athlete program was outed in the doping scandal, or when they hacked the Ukrainian power grid, or the troll factories.

The leaks just never make it to wiki leaks.

So was those leaked by local press or other institutions? Were those leaked documents also sent to Wikileaks and they refused to analyze or host them? If not I see no problem in the fact that you have many options on how/where to leak, especially if you are in Russia/China you will have a better reach tif you expose politicians and corruption if you use local (in your native language) press, the local journalists can also have the advantage they do not need translates,they are already in the country and can travel and verify things, they have contacts.