To add to your position on the subject, when I was on holiday in Kazakhstan, I'd say 90% of the young ethnic Kazakh I met in Almaty didn't speak more than very basic Kazakh, and 100% spoke Russian (at least better than me, I'm A2 at best).

I guess the number would be lower for rural areas, but even in Kegen (don't ask) I found my way speaking Russian without issue.

The only place in CA where I found people with whom I couldn't communicate in Russian at all was in Tajikistan, including Dushanbe(!).