The notion that the world is ending and ALL we are meant to care about is Dennis Quaid and his son is LUDICROUS!!!!! Why do American disaster film makers do this?
Film makers do this in disaster movies because having a sympathetic character with a story arc makes the film have an identifiable element for audiences to latch on to. If the film was just 2 hours of bad weather, destruction and people running from random natural disasters with no human story it'd be even more mind numbing than it already is.
I actually don't mind this film though, it's decent enough, far better than Emmerich's following film, '10,000 BC', which is probably one of the worst films i've ever clapped eyes on.