Casual well wishes - fundamentally flawed

At San Diego airport, prepping to board a flight home, I hear an airport worker bid farewell to some Brits he had been chatting with while we waited:

"Have a safe flight!"

Why "safe"? Don't we have enough experience flying people to and fro by now that safety is pretty much assured? Once the fundamentals of service are covered, shouldn't the customary departure wish change to "pleasant flight" - "good flight" - "rockin' flight" - "kickass flight", whichever best suits?

When do you decide that the fundamentals necessary for the business to function are taken care of and give the customer clearer priority? (If I have to shell out $ for any signs of food on a 4 hour flight and I'm not warned of that at the last pizza place before the gate, maybe some fundamentals still need tweaking.) Too many companies don't give the customer a role in strategy at all, and that's plain scary.