> Anyway just wanted to note there is no known policy that would stop rural flight.
High prices will do the trick, though. In Canada — which is said to have the most out of control housing market in the world — the urban population between the latest and previous census only increased by 4.8%, while the rural population grew by 6.5%. Due to periods of data collection, there could some COVID influence in there[1], but a similar trend was also seen in earlier censuses.
[1] If there is, that would be policy-driven, which you suggested isn't a factor, so...
> the urban population between the latest and previous census only increased by 4.8%, while the rural population grew by 6.5%.
One immediate question would be, how are the suburbs classified, urban or rural?
Canada defines urban as: A population center with at least 1,000 people and a population density of at least 400 people per square kilometer. Anything falling short of that is considered rural.