Allen, 10.04 My assumption would be that the former affiliations of individuals were well known where it mattered. The point is that those with extensive experience will have been sought for positions of weight and pretty much all fitting the bill will have gained their experience in important roles under previous conditions.
To choose instead people who have little of no experience would have been riskier by far, and a complete clean-out and exclusion was chosen much more recently in Iraq with utterly disastrous consequences (making the point). In theory, valuable lessons should have been learned by that time (Iraq), from the post-WW1 debacle in Europe - actually they were (viz Marshall plan, the progenitor of the EU, etc.) but then apparently forgotten again (or was it the "they're all ragheads, screw-em" that ruled the day ?).
Had the Iraq model been applied in Europe post-WW2 then, make no mistake, we would feel Covid was a minor disaster by comparison. And the UK would have had its share of misery, even now it would still be a basket case with debts way across the horizon, no resurrection from the war years, in a desert of a trading environment.
Individuals make the best of survival in the circumstances they find themselves. Once the regime changes, they adapt again. I have never been very keen on the idea of forcing a resignation/humiliation on some high publicity error which, as often as not, affected nobody at all.That sort of thing smacks of tribalism and/or vindictiveness together with lots of lower tendencies. To me it is self evident that people learn from their mistakes and never make them again, that much better for it (admittedly not everyone but the vast majority).