Excepting the aforementioned movie (which was very good, in my opinion), I think there is a simple reason for this: if Jesus’ second coming is not presaged by a rapture – wherein all the elect are removed from the world and a short(ish) period of tribulation, anarchy, unification, and ultimate destruction of evil – the stories would be very short.
If Christ’s return is more in line with what I believe shall occur (that it will be sudden, unannounced, and not presaged by more than at most minutes by any other event such as a rapture (though I do believe we will be “caught up together with them in the clouds to meet the Lord in the air” [1 Thes 4:17])), then movies about the end of time would be very lacking in their “crisis factor”. If there is no rapture in the way portrayed in movies like The Mark or Left Behind, there is no worldwide wondering what is going on, there is no wide-spread panic over where everyone has gone – it’s just done.
The crisis factor of having planes and cars crashing because some operators and passengers have suddenly been removed is a compelling part of a disaster movie – which is truly what most Christian end-times films are: they are disaster movies cast in a Christian light, from one (with slight variations) eschatological viewpoint.
One thing I do know about the end of time: when it happens, there will be no doubt in anyone’s mind what has happened. And when Jesus does finally return, it will be glorious for those who are His – and terrifying for those who aren’t.