Lonewolf_50, I'm sure you also remember from earlier discussions that the FOs had equivalent experience or better as compared to the Captain. All three were very experienced and capable. I'd not denigrate that in the least.
(That said, I was starting to entertain a scenario in which both had fallen asleep until the bouncing from the storm and the warnings for the iced pitots woke them up to pandemonium. But I don't think 15 minutes is a long enough time for BOTH of them to fall asleep at the same time unless there was a severe cabin air problem - say lack of O2 or some CO got into the mix. And even that does not work because at least one of them has an O2 mask on, I believe. So much for that concept.
(I've even entertained the thought that the WX radar had somehow malfunctioned. But that would have to take place in such a way that the equipment itself would not notice and report it to ACARS for replacement at the next stop. There aren't many places that kind of failure can take place if even rudimentary monitoring is included in the design. It's another low probability thing. But it would explain their flying peacefully into disaster.)