Personally I cannot fathom how the road warriors onboard would not have inquired about their arrival time, but bear in mind they only flew 150 miles PAST their destination, which is about 15 - 20 minutes. Not everyone would be immediately concerned that they had not started their descent/ initial approach.
I understand they were flying at 37,000 ft., so if there was cloud cover at any altitude below them, folks might have missed landmarks.
Also, they (pilots) might have inadvertently entered an incorrect frequency on their radio after being ‘handed off’ from one controller to the next.
There’s reasons why they could ‘lose’ radio contact.
BUT ... in an A320 I cannot believe the nav system/ flight computer wouldn’t have nagged them terribly about waypoints.
This is one for the books.
Any good stewardess is watching the clock....They have a job to do prior to landing.