Technically, there's a difference between large neutrals and wastelands. Although players may consider any big neutral a wasteland, nothing in the in-game UI calls it that. Technically, the other examples you site are abandon/blockade cards or boots/surrenders, not wastelands.
This wouldn't normally be a big deal but the game links to this wiki page when you click the question mark next to the Wasteland setting (either when creating a game or viewing a game's settings), and adding information about blockades, abandons, boots and surrenders here just makes it more confusing. Perhaps this information would be better on a page about neutral armies. Fizzer (talk)