While not exactly the same scenario - it does involve not getting notifications from AS via email or text.

Friday 5/20 Flt 563 LAX/PDX 8:00am scheduled departure.
Check in online the afternoon before - noted a 7:20am boarding time. Arrived at airport at 6:45am - notice that BP now shows boarding at 10:02 for a 10:42 departure. No email or text sent. Oh, well.. go have breakfast and wait it out in the Boardroom. About 9:00 - I notice my BP now shows 12:02 boarding for 12:42 departure. Staff at BR front desk "shrug" their shoulders - concur that the flight is delayed with a slight motion toward the departure/arrival screens on the wall to the right of the desk. They suggest I try the Cust. Svc desk to the left as I exit the elevator. They failed to mention that it was a little bit of a hike, up the escalator and "hidden" behind the "Blu Sushi restaurant/bar". Agent confirmed delay was mechanical - diverted SLC/LAX flight to LAS for fuel related issue. No later flights were available, flights through SEA got me in later than delayed direct. I looked at a 1:10pm on Delta (9:25am Delta flight was available but too close to departure time to make it another terminal to board) - So I decided to wait to see what would happen rather than force a rebook for a less desirable itinerary. I called the MVP Desk - informed them that I was not getting any flight delay notification (despite making sure that the requests for such notifications was indeed set to "on"). Agent said she would notify IT. Went back to BR to wait it out. Asked at front desk of BR if they could make announcements if anything changed on #563 as there were many people in the BR on the delayed flight. They assured me they could. At 11:30am - BP now shows departure at 3:30pm. Not a peep from the front desk. No email - no text - nada from AS as far as communication about delay. Use my phone to book the 1:10pm on Delta - decided to use miles in lieu of $$ as fare had doubled from my first look at 9:30ish until 11:30am. Called MVP Service Desk - informed them of my self rebook and requested that value of LAX/PDX be placed into my "wallet" - it was. Noticed when I landed in PDX (on time) at 3:30 that #563 was now delayed until sometime after 6pm... didn't pay attention to the details as I was now home....

I'm very disappointed that the AS notifications weren't being issued. The lack of such timely notifications prevented me from making alternative arrangement much earlier than I ultimately did. Had I known earlier - I could have booked the 9:25am Delta flight and been home at 12:00. I feel sorry for those people who sat at LAX all day waiting for the 8am flight to depart at 4 something pm.