There's really no mystery to why similar movies get made. The bottom line is that movie studios are in the business of making money and the best way they can do that is to buy great scripts. Typically, great scripts start with a great concept. Both Olympus Has Fallen and White House Down just happen to have the same killer concept - "Die Hard in the White House." When they go to determine the release dates for the film, the studios will jockey for the best position to win over audiences, hoping that their movie will win out.
There are plenty of other copycat movies out there, so feel free to keep the debate going in the comments. In the meantime, let us know what you think of our winners and losers, and tell us what White House movie you're more excited to see.