You have some incorrect information about Russian regional airports.
For example, there are:
2 everyday flights from Bratsk to Moscow, Novosibirsk, Krasnoyarsk (2 flights to each!) using Tu-154 from 1990 till our days
1 everyday flight to Krasnodar, Yakutsk
15 everyday flights to Irkutsk on Yakovlev-40 and 42
3-4 everyday flights from Irkutsk to Beijing, Vladivostok, Krasnoyarsk, Novosibirsk on Tu-154
Irkutsk to Moscow: 1 flight on A310, 1 on Tu-154, 2 on A320, 1 on B767, 1 on Il-62 and 1 on Tu-204 - more than 1000 pax per day!