The 'security' we have today may well be so much 'window-dressing', but it's the biggest display that the travelling public is prepared to put up with either in terms of cost or time. If either go up significantly the travelling public will either choose not to fly or fly much less frequently.
I certainly travel much less often to the US than I used to - 1 1/2 hours to get through US Immigration, broken lap-tops and surly security staff, I can frankly do without...
El Al may well have the most comprehensive Airline Security on the planet, but I bet you the wished they didn't have to do it - and I don't see many Airlines queuing up to emulate them 'cos it won't sell very many seats.
Airlines sell a product in a pretty tough market. Margins are thin are profits are hard won. In terms of security we have what we're prepared to pay for - no more, no less...