You missed some…the Mini-Pizza Maker, at least.
The problem with the interchangeable molds is that the cost of the base unit goes way up. And most people wouldn’t ever buy the other molds…and even if they did want them, they’d probably be at least $20 each.
I have a Cuisinart Grill/Griddle/Panini thing (purchased from Woot! for $40-ish) and it has optional plates to turn it into a waffle iron. They’re $40 at Amazon, which is a discounted price. I can buy a decent waffle iron for half that price.