The deluge of superhero movies this summer could spell saturation for a genre that is exhibiting a serious lack of adventure.

I paid for a double bill of Marvel Entertainment movies last weekend – X-Men: First Class followed by Thor – and feeling numbed after five hours and hundreds of millions of dollars in lavish production spend, I came to a worrying conclusion: the superhero movie is doomed.

Of course being over 40, I am not the target demographic, and so far these films are showing little sign of box office fatigue. The X-Men origins movie – the fifth Fox movie in the franchise in 11 years – took $61m in the international markets and $55m in domestic last weekend. Thor is now on $258m in international and $170m domestic.

The investment of money and talent that goes into creating the myths in these movies – with a view to building franchises out of each – is staggering. Both Matthew Vaughan and Kenneth Branagh did bang-up jobs with their individual tasks of telling “beginnings” stories, but as an avid popcorn moviegoer who has a healthy desire to be riveted, I found myself merely rather bored with the predictable set-ups and even more predictable showdowns.

The movies are trapped by the conventions to which they feel they must adhere. Comic book movies are by their very nature two dimensional and the moral complexities they contain are not very complex at all. They might be intriguing – certainly the X-Men franchise plays with notions of kids as outsiders, possibly a metaphor for ethnically diverse or GLBT kids. Bryan Singer even had a mutant “coming out” to his parents in the franchise best X2: X-Men United. But that’s as far as it goes. The mutants are given a simple comic book motivation for being at odds with the world and nothing changes after that. They remain conflicted because they have to for the ongoing conceit to work.

Green Lantern follows from DC Comics and Warner Bros in ten days’ time. Captain America: The First Avenger arrives in July. More Nolan-directed Batman and a Nolan-produced Superman reboot follow next year. Marvel has The Avengers in production and Antman set for production as well as sequels lined up for Iron Man, Thor and Captain America. Sony’s The Amazing Spider-man arrives next year just five years after Spider-man 3. It’s exhausting to think about the volume of these movies over the next decade.

But I can’t be alone in finding these fantastical epics narratively uninspired and ultimately unsurprising. And when will the sophisticated teens who are thus far lapping them up start to yawn at the endless retreads of genre conventions? Christopher Nolan effected some change by shaking up Batman with unforgiving violence and actual death (let’s face it, Maggie Gyllenhaal won’t be coming back for episode 3), but the benign, PG-rated heroes of summer 2011 are wearing thin on this ticket buyer.

Alas, as studios line up their gleaming new superheroes for box office battle, the last in the Harry Potter franchise hits screens next month. Now there is a mythology (based on a series of novels, not comic books) which can happily sustain eight films because of the originality and richness of JK Rowling’s stories.

At the risk of sounding like an old bore, how many more superheroes can our minds and multiplexes handle?