> The events of the last few days make it at least plausible that Putin's days are numbered.

Citation needed. I believe Putin enjoys a very strong approval in Russia and I have never read or see anything that could disprove it (except from self styled experts that are notoriously clueless about everything).

For a comparison there were just hundreds of protestors in Moscow on a 12 millions pop. This is nothing.

I visited quite a few Russian blogs with the help of a translation plugin, I didn't see anything looking like they disapprove, on the contrary most of them ask why it took 8 years.