It's not like the Soviets fared much better with regards to corruption and institutional decay, to the part where the rampant corruption of the Brezhnev-era was a major contributing cause to the eventual collapse of the union.
Institutional longevity is largely an unsolved problem. Seems having checks and balances like the US does helps slow it down to some extent, but is far from a guarantee.
Not sure I follow the link to the Soviets, but yes they certainly excelled at letting too few people accumulate too much power too. If only we were able to learn a little more from history.