Just imagine children (or adults) listening to operas on CD, learning to identify characters, and "staging" operas at home. There could be interactive "kits" to build small stages, and panels that could be made into sets. Nothing would be as technically elaborate as puppet operas, but there could be a lot of room for making characters "modular." The characters could be supplied with costume changes (and masks, when necessary) that snap on to their little plastic bodies. They could even have little holes where their feet are, and the stage could have little groves so that the can move while they sing (being controlled by sticks that go through the grooves in the stage and go into the bottoms of the individual action figures).
The action figures could be sold in opera "kits." Don Giovanni only has 8 principal players, so its kit would consist of 8 figures (including a "stone guest"). The "stone guest" would be the only figure that would not be able to work in any other opera (being a statue representing a dead Commendatore), but the other characters could also double as extras in other operas. The kits could also come with large sheets of paper and mounting frames so that people could design their own sets. There could be instructions about different kinds of media that can be used--watercolor, crayon, colored pencil, charcoal, and collage. Some clever person could even design an easy way to mount the sets on rollers, which could snap onto the frames. The kits could come with suggestions for making props (out of clay, maybe?), and set pieces (tables and beds).
I imagine that any parent buying this kind of thing for their children would end up playing with them as well. Gee, the kids might even want to go to actually see an opera, once they know the characters and the arias. They might become experts on staging and set design before they are even old enough to read the super titles. Before that they might just sing everything in Italian. Or German. Or French.
Imagine the action figure set for Wagner's Ring! The kits could be geared for different age ranges, with the more "adult" operas saved for later adolescents or adults. My mind races at the thought of the set of action figures for Salome.