Putin has an 83% approval rating in Russia. That's an average of a international media poll, a state poll, and an independent Russian poll.

Polling isn't perfect, but even if it's off by 30 points a majority of Russians support Putin. Every single Russsian politics watcher rates the odds of a revolution or internal coup to be exceedingly low.

We need to accept the that the Russian people are unable or unwilling to see reality here. They believe in the cause. At least as it's been presented to them. They seem to really think they're the liberators here.

Edit: Bolded the important part so that I don't have to keep telling people to read my comment.

Edit 2: The political science on this points to Putin's popularity among Russians being very real and quite durable.