It has been a particularly miserable summer for original movies. Elysium — the highly anticipated follow-up film from District 9 wunderkind filmmaker Neill Blomkamp — just opened with an estimated $30.4 million. That figure isn't awful; it's Matt Damon's best debut since 2007's The Bourne Ultimatum, and Jodie Foster's best opening since 2002's Panic Room. But it is $7 million less than District 9's debut four years ago, and, more to the point, it is conspicuously lower than the debut grosses for movies seemingly aimed at the same audience, like Iron Man 3, Star Trek Into Darkness, and The Wolverine.

Of course, all those movies were sequels, based on properties that audiences have known about for decades. But even World War Z, based on a bestselling novel from 2006 — and which faced an onslaught of bad press preceding its release — opened with $66.4 million, more than double Elysium's debut.

This is hardly a new phenomenon; original properties have been an endangered species in Hollywood for several years. But this summer's wide releases put that gulf into particularly stark relief. Take a look at the chart below: