It is fairly simple really.There are multi millions of government dollars raised from taxation that needs to be distributed to friends of the government. They can't just hand it over , that wouldn't look good so the best way is to create problems with very expensive " solutions" i.e. terror threats. This creates fear amongst the general population and makes them happy that the government is doing something to make them "safe".
Hence the farce that is airport security since 9/11 . In fact the farce in the middle east right now in the name of "humanitarian rescue"
Security and wars are big business and big bucks for both those in government handing out contracts copping the kickbacks and to their mates in the military industrial complex , all to make us feel warm and fuzzy and "safe".
Fear Pays: Chertoff, Ex-Security Officials Slammed For Cashing In On Government Experience