Thats why i said it's about the pipeline. UFC belts have a very high turnover, you don't assess dominance by # of belt holders imo. Russia has high level contenders at 135, 145, 155, 170, 185, and 205. They used to have a couple at 125 (Askarov and Mokaev),..so there's literally only 1 division where they haven't made their presence felt (HW).
There was a time when Nigeria had 2 belt holders (Izzy and Kamaru), now they have zero belt holders. But Nigeria not only doesn't have beltholders they don't have anyone in the pipeline, so it was never a dominant region, just a flash in the pan. Same can be said for Georgia, this is their golden era, but where is the pipeline of Georgian killers in the UFC? It doesn't exist. And btw, you can't chalk it up to Georgia's size, Dagestan and Chechnya together have roughly the same population as Georgia. And pretty much all the Russian contenders are from Dagestan/Chechnya.