I've always viewed TCAS as another tool, much the same as Wx Radar. Equipment knowledge, interpretation and situational awareness by the operator is required with Wx Radar, it is then up to the operator to maneuver the A/C to avoid the "lumpy stuff".
Experiencing an RA in real life or in the sim while IMC, leaves you charging after a computer generated solution (escape maneuver) without visual / oral confirmation of some sort, and is disconcerting to say the least. Upon receiving a TA/RA, my first reactions are; check my altitude, eyeballs outside - then lights on, day, night, VMC or IMC. The gee whiz marvels of today’s technology are tools that still need old fashioned airmanship for backup.
Missing radio calls is nothing new, we've all done it, as our undivided attention is not always placed on that com box (aviate, navigate, communicate). A disturbing trend that I have noticed amongst aircrew is both pilots switching to I/C to communicate with the cabin, or both monitoring the ATIS while simultaneously monitoring ATC - seems simple enough - but maintain the S.O.P.
My above comments are in no way meant to speculate on the cause of this particular accident, only to bring forth some basic fundamentals that we should all look at as means of additional preventive measures as we continue to fly safely.