The lacklustre perfomance of Green Zone has proved again that cinema audiences are not enticed by Iraq war dramas but more than that it could mark a turning point for high-priced movies with message.

Paul Greengrass’ new movie Green Zone is an engaging blend of action thriller and political statement, which is set a month after the invasion of Iraq in 2003. Greengrass employs all his talents to immerse the audience in riveting on-the-ground combat while telling a fast-paced story about a US chief warrant officer exposing a US government cover-up. The folks in Washington, he discovers, know that there never were any WMDs in Iraq.

But alas, not even Greengrass, Matt Damon and a conspiracy thriller set-up straight out of the Bourne movies could entice mainstream audiences to this particular Iraq movie, which opened on a lacklustre $14.3m in the US and $9.7m in 14 international territories. Budgeted somewhere north of $100m, Green Zone is a big disappointment.

It’s also proof, if proof were needed, that audiences just can’t get comfortable with going to cinemas to see movies set in Iraq - or Afghanistan for that matter. Be it Lions For Lambs or Stop-Loss, Body Of Liesor Brothers, In The Valley Of Elah or Home Of The Brave, the audience just doesn’t want to go.

Ironically, World War Two movies have the opposite effect on audiences: Inglourious Basterds was one of last year’s biggest hits while throughout the last decade Atonement, Letters From Iwo Jima and Saving Private Ryan have all proved significant crowdpleasers. As if to confirm the perennial fashion for World War Two combat movies, HBO is launching its $150m mini-series The Pacific this month.

Even Vietnam proved popular with cinema audiences in two waves – one in the late 1970s (The Deer Hunter, Coming Home, Apocalypse Now) and one in the late 1980s (Platoon, Born On The Fourth Of July).

You can certainly attribute the failure of today’s films to a general distaste for the current conflicts. It’s hardly inspiring for mainstream US audiences to have Matt Damon prove that US troops are dying in a war based on a lie.

But audiences today are just less interested in going to the movies to see social commentary than they used to be. Green Zone proves that you can dress your war stories up in as visceral and exciting a package as possible and you still can’t lure audiences in. It is 24 years since best picture Oscar-winner Platoon grossed $138.5m in the domestic market and shook a nation in its depiction of the hell of the Vietnam war. This year’s best picture winner and perhaps the definitive film about today’s war -  The Hurt Locker -  took just $15.7m, the lowest grossing best picture winner in history.

So what happened? When did contemporary issue movies become specialised niche titles that are lucky to gross over $30m?

The answer is perhaps linked to what wide audiences want to see in a cinema and what they prefer to watch at home. The big screen is no longer necessarily the place for thought-provoking or challenging film in the eyes of the internet generation, who want only the biggest visual and aural thrills from their out-of-home experience. That means Avatar or Alice In Wonderland. This summer it will mean Toy Story 3, Shrek Forever After, Iron Man 2 and The Twilight Saga: Eclipse. It means 3D, IMAX, special effects and escapist spectacle on an unprecedented scale. They don’t want to have to think.

That doesn’t mean there isn’t a place in theatres for issue films or Iraq movies. They just have to be made at a reasonable cost and their biggest market might ultimately be video-on-demand or DVD. The vast majority of people who saw The Hurt Locker, which was made on a modest budget of under $15m, watched it on a small screen in the home. That may not be where Kathryn Bigelow and her DP Barry Ackroyd would ideally wish it to be seen, but that is the new reality for many film-makers.

Indeed Green Zone, which will probably reach a wider audience on DVD than in theatres, might be a turning point for high-priced movies with a message. From now on, meaningful cinema might move strictly into the specialised domain.