Fall of the Soviet Union was mostly an internal coup supported by the street rather than a popular uprising.

It's still "Russians knocking off their leadership".

People aren't expecting Russians on the street to get rid of Putin. They're expecting that it will cause pressure on other Russian leaders to side with Russians and the West over Putin...

There are no 'other russian leaders'. Putin's political theater before the war was clearly aimed to make any russian official of note into an accomplice, publicly supporting the invasion. They have all made their bones and are all sanctioned by the EU and world countries now. So this course of events is highly unlikely.

Part of the risk of being a strongman-style leader is there's always someone waiting in the wings, and they don't have to have been previously prominent.

"Why are coups always led by colonels?" https://foreignpolicy.com/2010/02/22/why-are-coups-always-le...

There always is someone willing to cut a deal to save themselves... And the west will facilitate it.