The luxury housing market had a strong year in 2021. High net worth individuals continued to buy and sell homes at a quick pace as they and their businesses generally thrived amid the continued trend of working from home. As a result, many luxury agents had outstanding years. The percentage of existing single-family home sales priced above $1 million also shot up this year, which helped agents in this market sector, as home prices across the country more generally surged. But 2021 also saw some significant shakeups in the luxury real estate world — a number of acquisitions changed the scene and a major industry figure stepped out of the…