This is the result of (1) wealthier buyers (2) increased urbanization and (3) housing supply still playing catch up from 2008.

Nicer reasons than say, stagflation.

The buyers are likely to be overseas property investors - there is a lot of this in London

Yup, I purchased a house in the Seattle area in 2016 for 12% over the asking price. This year it appraised for 58% more than what we bought it for. Houses are regularly selling for over >10% over asking prices as soon as they're listed