Ignore Terminator Salvation's US box office and look to Britain, where it's just had the best opening weekend of 2009 so far... replacing the previous holder of that title, X-Men Origins: Wolverine. Why is Britain more accepting of shoddy sci-fi?
The Guardian reports that Salvation made £6.94 million in its first weekend, topping Wolverine's previous 2009 record of £6.66 million. This despite both movies receiving equally bad reviews in the UK as they did in the US, so it's not as if they gained some extra credibility and/or quality on the trip across the Atlantic. So what's going on?
It's not as if the UK is so science fiction-starved that they'll go see anything; yes, Doctor Who is having a half-year off, but British audiences have just finished new seasons of Ashes To Ashes and Primeval and have Torchwood returning in little over a month. Perhaps, then, the subject matter of the movies have just captured the British imagination more readily than they have the American. While US audiences shied away from the American dystopia of Terminator and evil-military of Wolverine for reasons of events still in recent memory, British audiences have more distance on those concepts - and, perhaps, more eagerness to see America get trashed. Perhaps they see it as karmic payback for the international upset caused by the Bush administration.
(This idea - that non-American audiences may be more in tune with things going wrong for Americans in movies, because they're (a) not living in America, currently trying to continue the Obama-sque feelings of optimism, change and hope despite economic meltdown and coming to terms with what the War On Terror did to the country's moral certainty and (b) instead looking for some sense of international schadenfreude because of said War On Terror and resulting unintended political diplomacy mishaps - may even explain Terminator Salvation's international box office almost matching its entire US take in its first weekend.)
Alternatively, there's always the possibility that the drearier British summers may have had something to do with it; as the Guardian notes,
As with all films currently in the market, Terminator Salvation benefited from dismal weather.
Perhaps that's the next big thing that Hollywood should hope for in the American market, instead of giant robots and old school superheroes; more rain.