Frequent enough to be well known; condo owners that bought prior to them being built were told they’d need to pay an extra $X because the builder could get more for them after they were built (housing prices were more)

It is also fairly common for a contractor to relist if there’s a complaint against their company

The rest I am unsure of but they sound plausible, there is too much need for skilled trades because boomers a lot of time refused to grant people working under them apprenticeships, instead just using them as labourers that way they could charge more and not be replaced.