Fact; If in case of RA2 failure (e.g. readout difference between the two) A/T automatically uses RA1 as fallback, then this most likely would not have happened. It is single device dependancy w/o backups (or clear system feedback) that creates dangerous situations.
We can have a long debate as to pilots becoming computer programmers or staying airmen. Fact is these days you cant do w/o computers and the complexity understanding the dependancies are, to say the least, challenging as we see again and again.