"Now, most of those farms have been sold off to mega farms or handed off to kids that don't really want to be a "farmer"."

It's common practice that the person doing the farming may not be the land owner. Field leases are extremely common. So they can inherit the land and just lease the fields until they decide to sell to a residential developer for big money as the urban sprawl encroaches.

The vast majority of farms are not in danger of urban sprawl. Farms near cities are but there is a lot of land not close.