Russian oil revenues are at near record highs though so we’re still a long way from any kind of collapse.

As far as I know, the USSR collapsed because Gorbachev’s reforms weakened existing institutions and power structures, without providing replacements.

*Poutine

With a government relying for a substantial part on income from such an industry, any collapse of that industry will be a serious problem. Especially in a time where they need each and every ruble (or dollar, if they can get them).