How Many Superhero Movies can a Summer Sustain?

J, myself and my son saw the Hulk over the weekend (I saw it twice). It was a lot of fun, but while watching the previews, I realized what a crowded summer it is for superhero movies:

1. Ironman
2. Hulk
3. Hancock
4. Batman sequel
5. Hellboy 2
6. Wanted

Not to mention The Spirit which is coming out at Christmas. It's also clear that Marvel is making a stab at a truly expansive Marvel Universe imprint on the big screen in the next 3 years. Nick Fury is in the credits of Ironman proposing a new team. Ironman shows up in Hulk to the General proposing a team (probably wanting his super soldier serum, if I had to guess, to make Captain America). Next two summers we're going to see Captain America, Thor, and then the Avengers, and possibly even an Antman (Henry Pym) potentially. Sam Raimi wants to make a fourth Spiderman. If the Avengers concept works, then of course you'd expect DC to attempt the same thing and start exporting the larger DC Universe, too, plus more Batmans, Supermans, too. At what point do these superhero movies start cannibalizing one another, instead of expanding the market altogether? Think of it in the limit - maybe you can have 2 superhero movies in a summer than make $800 million total. But diminishing returns kick at some point. Can you have 100 superhero movies in a summer making $40 billion? No, you can't, because domestic revenues are only at around $12 billion if I'm not mistaken, annually.

I think this is monopolistic competition. Even though each comic book movie is unique, the low entries to barrier is going to push economic profits down to zero. But, I suspect that the longrun equilibrium is still a positive number of comic book inspired movies.