It is gross oversimplification. It's basically political/special service elite (bound with personal loyalty) and thick layer of rent seekers (from oil & gas billionaires to countless bureaucratic sinecures).
Even if we assume that all power is indeed in hands of one person, who will gain power once he is killed and current system collapses? Ones who can act fast and are not hindered by too much reflection or morals: junta, blackshirts and organized crime.
>run out of money
No. Point is making desired behaviour more profitable than current behaviour for regime stakeholders. When risk coming from asset freeze becomes larger than risk from change in government - system will start to transform.
>holds passwords
That doesn't work that way. It's actually opposite - wealth is often spread among many loyal figureheads, with actual beneficiary holding nothing on his name.
>Norko
Russian regime is as far from classic totalitarian one as it is from european democracy. Probably even further, as it's basically democracy corrupted to the point of switching to new aggregate state.