First a totalitarian state, then a corrupt shithole that brought everyone around down with it. Same difference...
Russia has oil to sell; most of ex-USSR countries don't. Nevertheless they enjoy priority in trade and immigration with Russia. They get investements, price cuts and sometimes direct monetary support from Russia.
The oil and gas trade is good for both sides. It's not like Russia is some benevolent country that provides for others, they sell resources for money and influence.
But soviet rule was shit. It institutionalized a system and a whole kind of thinking that was unsustainable, which then devolved into chaos.