The Hollywood star system is shrinking. As the movie business forges deeper into the comic book canon, it matters less and less whose face is behind the mask. There remain a few exceptions. Robert Downey Jr., Jennifer Lawrence, Will Smith, Melissa McCarthy and Ben Affleck still guarantee a certain level of box office success in the right kind of project. They still have the clout to guarantee that movies — even smaller, more challenging projects that give bottom-line-oriented executives agita — actually make it to screens.

But with true stars becoming an endangered species, there’s a talent grab taking place that’s causing heartache and delays for companies hoping to package films at this year’s Cannes Film Festival.

“A lot scripts are all going out to the same list of actors,” said Peter Kujawski, Focus Features chairman. “You need to give them a chance to read the material and engage in the process, and it takes time.”

The problem has been exacerbated by scheduling difficulties. Downey, for example, has appeared in an Avengers movie or a spinoff in four of the last five years, and he has three more stints as Iron Man slated in 2017 and 2018. And now that Affleck’s joined the Justice League as Batman, donning the cape and cowl will become essentially an annual occurrence for the actor. As these comic book universes expand, so do the demands on the time of top-tier actors.

“Those big Marvel type movies all come with big multi-picture commitments and promotional commitments,” said Marc Schaberg, co-president and COO of Sierra/Affinity. “It adds up to a lot of time.”

Television is exacerbating the problem. It used to be that the small screen was the last stop for movie stars whose careers were in a death spiral. No more. Ever since Matthew McConaughey and Woody Harrelson’s star wattage intensified thanks to stints in HBO’s “True Detective,” top shelf actors have been flocking to limited series and shows. Amy Adams, Reese Witherspoon, Nicole Kidman, Woody Allen and Josh Hutcherson are among the cavalcade of actors slated to pop up on cable or on streaming services programming in the coming months and years.

“I think TV is more of a culprit,” said Nadine de Barros, co-founder of Fortitude Intl. “It makes it much more difficult to schedule things. It can take up half of an actor’s year.”

Cannes remains perhaps the most important market for launching independently funded films. The goal for film financiers and sales agents is to hit the Croisette with a slew of compelling projects adorned with buzzy directors, writers, and stars.

However, some agents say that having all the deals in place is more important than taking the Riviera by storm with a splashy packages only to have filmmakers and talent fall out after the glow of the festival wears off. Sometimes that means skipping Cannes if the elements don’t align.

“Things are much more buttoned up now,” said Graham Taylor, head of global finance and distribution at WME. “People don’t want stuff sold without the actor deals done and the financing lined up.”

Late last week, many distributors noted that things remained very much in flux on the acquisitions end of the business.

“The agencies haven’t announced any of their screenings yet,” said Bill Bromiley, Saban Films president. “It’s always this way. They wait until the last minute and then you have to rearrange all the meetings you set up so you can see the presentations.”

It is, film executives note, a problem of their own making. Having a name actor guarantees a film will get made, but failing to take risks on emerging talent limits the pool of talent available to guarantee a greenlight. And so the pantheon of Hollywood A-listers grows ever more rarefied, and precarious.

“We’re all chasing the same handful of bankable stars,” laments Lisa Wilson, co-founder of The Solution Entertainment Group. “It’s rare that somebody new pops.”