I think Apollo hits the nail on the head!
As a passenger when you get on an aircraft for X number of hours you are completely handing over your control of all significant safety concerns to the crew of that aircraft and the company they are working for. Personally I'd considered that a major responsibility and would expect the airlines to take it very seriously.
Obviously there is always a trade off. Being safe costs money and although there is always more you can do it tends to get exponentially more expensive to do so, eventually a line has to be drawn somewhere. Its a bit of an oversimplification but I guess ultimately the market (i.e. the passengers and what exactly they are prepared to pay) is the driving force which dictates exactly where that line is drawn.