it is VERY easy for them to become so distracted that they forget to do their primary function - IMHO the blame sits firmly with Boeing, they should not have released a system that allows the system to effectively ignore conflicting information WITHOUT warning the crew that there may be an issue
sorry mate, absolutely 100% disagree - what you want there is effectively pilotless aircraft - cannot happen for various reasons. Despite the apparent opinion on here by bystanders and flight simmers and the general public, the pilot still flies the aircraft and doesn't just push the odd button and sit back to sudhoku and cups of tea. The automation is there to assist us in flying the aircraft, but absolutely does not absolve us from being in charge and responsible for the aircrafts performance. You either accept that or you design a pilotless airctaft. anything else is just adding another layer of automation - which is largely irrelevent and would just cause more confusion.
The failure in this instance should have been absolutely insignificant - infact if you use your techie software approach you will find that the reason that the system is designed thus is not an oversight or mistake by boeing but in order to ensure that it doesn't plough into the ground on a cat3 approach. The rad alt is primarily designed for cat2 and 3 autolands and GPWS, it is thoroughly irrelevent in all other aspects of flight.
Besides the crew (aparently) ignored a significant number of 'warnings' (pitch, noise, airspeed indicator, thrust lever movement, FMA annunciations and more) - you really think they would have noticed another one!
I also see an interesing aspect of our modern society in this discussion. i.e it must be someones fault - lets invent another layer of oversight to fix this one issue etc etc. And in todays society I can understand why some people have a problem understanding the fact that the pilot is responsible for his actions - that is a concept that a whole generation cannot appreciate as they have been bought up in a world with no responsibilty or consequence.