Do you know anyone who is even passively "into" board gaming who never owned at least one of those?
I know a lot of people who are into boardgames who have never paid money for any of those - i.e. their parents may have owned them, but not them. They played them growing up or at other people's houses though. And you can bet they probably have paid for Scrabble at least once, which is Hasbro in the US/Canada (not elsewhere).
The themed Monopolies seem to sell primarily to three groups of people:
1) Obsessive collectors (who don't necessarily even like boardgames, but "must have" the Monopoly for their specific interest).
2) The much, much bigger market of "people who know you like thing X, and want to buy you a safe and memorable present". Anyone from grandparents to those acquaintance-y sort of friends certain people seem to have dozens of. This is how most of the "themed" Monopolies I'm aware of in the houses of friends got there.
3) "people who just wanted to buy Monopoly but all this stuff is around the same price and like like thing X so what the hell!".
One friend has like four different themed Monopolies he didn't buy any of, and I know all of them came from various acquaintance-y friends, who know he likes boardgames, and likes, say, Batman, so here's the perfect marriage of the two, right?