The odds of a full on anti-Putinist purge seem a lot higher with a disorderly succession compared to one that Putin orchestrates himself. There are risks either way of course, but it doesn't seem like such an obvious choice for him as many imply.

Yeltsin, Gorbachev, and Khrushchev all died peacefully.

Yes, but did they groom a successor? Yeltsin did (Putin). Krushchev - not sure, I think there was a bit of a tussle. Gorbachev was probably too young to be thinking about a successsor - and he was essentially shutting down the Soviet Union.

Khrushchev was overthrown. Gorbachev was basically too. After the hardliners’ coup attempt he was basically a lame duck.

Yeah I think casual observers miss the fundamental political apathy of most Russians.

Overthrown leaders don't have a power base; mobs aren't going to turn out to return a deposed leader to power. Once they are irrelevant, they're going to stay that way, and everyone knows it.

Lenin himself died of natural causes after leaving power.

Lenin isn't a good example. He had a stroke while still in power and never effectively regained it. He was reduced to reading the newspaper in his wheelchair and crying about developments, while being unable to effect real change any more. He arguably did not want Stalin as his successor, but was powerless to prevent it by then.