This.

Is Omicron innately less lethal or is it less dangerous only in populations with few-to-no remaining immuno-naïve people?

My understanding is that most theory and evidence points to the latter as the main factor. The best vaccinations, and prior infections, are highly protective against severe outcomes even once short-term and sterilizing immunity have faded.

But the only way to prove this for sure is to let China conduct its natural experiment. And they’ve no choice, the Party squandered literal *years* in which it could have near-universally rolled out a foreign vaccine in favor of politicking and propaganda.