From what I understand about large Ontario holdings, they were originally railroad land leased on long term leases, not actually purchased until recent times.

Haven't heard that angle. In SW Ontario, much of the land was granted by the Crown as "Concessions" - land given to someone for service to the Crown. Today in the area where I am invited to hunt, most of the roads are described as "4th concession", "5th concession", etc.

The marsh I shoot has been owned by the same American family for something around 80 years. At the time that my friend's grandfather bought the property (500 acres or so) his friends all kidded him about spending money for a soggy piece of marsh. Today, it's worth millions, I'm sure

I understood the Crown gave such concessions to the railroad, something like 25 or 50 miles on each side of the tracks. In turn, the railroad was allowed to sell or least such land to finance their operations. Don't know the details, but it sounds like a good deal if you had a few bucks at the time.