Airlines and "lost" luggage items

So why is it so difficult to get back something missing after an airline flight? Are airlines trying to further deter people from wanting to fly?
I had an expensive item missing after a recent flight where my suitcase had a TSA inspection notice in it when I got home. After a week's wait from my email (I was told on the phone it would a 90-minute wait) request, when I finally got the TSA claim form, I was appalled at all the information the TSA prefers to have.
Another person I know had an expensive camera missing from luggage that had been in the possession of one airline only. The luggage showed up more than 24 hours after the flight landed. Upon notifying the airline, the passenger was told he should have called within 24 hours!
If such a reply is something other than tacitly condoning theft by the airline's employees, what could it be?????