It's actually not true that family dairy farms in Ontario are doing well. If you look at actual data (search for "D056 Number of farms with shipments of milk by province"), you'll see that the number of independent farms in Ontario has declined by 29% since 2006. You see the same long term trend in every province.
At one time long ago, the quota system was billed as protecting the family farm, but in practice now it drives the death of family farms, as people with quotas slowly sell out to large producers and new farmers cannot enter the marketplace because of the quota cost wall. Ontario currently is tied with Quebec for the cheapest quotas in the country, but getting started in the industry is still impossible without huge investments beyond the reach of young farmers (e.g., the upfront cost just to buy just the quotas, not the land or the cows, for a small 100 cow venture in Ontario is currently $2.4 million -- compare this with someone else in this thread who managed to get a whole farm up and running in the US, including land and his herd, for around $500k USD).