It almost happened like 2 weeks ago. It is really boiling inside Russia.

That seems like a rather false hope. Russia doesn't have much of a track record for backing down.

We can discuss the Prigozhin incident but no one outside of Wagner supported him. Nor does he seem to be in favor of withdrawing from Ukraine but rather assigning blame for mismanagement of the war. In fact, there are a whole host of vocal Russians ("ultranationalists") who seem to think Russia (and therefore Putin?) is not putting in enough effort.

If there is a coup, the rest of the civilized world really may not like whoever replaces Putin.

USSR fell apart, when the people saw their government and system as a complete fraud. Much to the surprise of Kremlin watchers. There is still hope for the Russian people

One would hope but I recently watched a YouTube video of an Australian touring a shopping mall / grocery store in Moscow. It looked practically identical to a western version. Contrast that to the USSR where grocery shelves were routinely empty and there was no variety of items.

Now maybe this is some kind of well funded information operation and sanctions really are working but there is no way the level of austerity is anywhere near the USSR's terminal levels. Until the Russian people's daily lives are adversely affected in a huge way, the comparative dissolution is not happening.