I think you are sidetracked by this proposed obstacle-avoidance software. Let's look at the feasibility of the original proposal, which was an autopilot sub-mode that would fly the plane to its best glide speed in case of a serious engine failure.
From a flight safety perspective, it can IMO be treated much like the stick pusher stall prevention device. The functions are in fact quite similar.
The basic difference is that in this case the primary trigger signal comes not from the AoA sensor but from a thrust deficit sensor. The autothrottle already incorporates the function of such a sensor, presumably engineered to flight-critical reliability standards, thus it already exists.
This
document from Transport Canada specifies the reliability requirements for stick pushers in transport category aircraft. It says the probability for failure of the device to operate shall not exceed 10^-4. Furthermore, regarding the probability of unwanted operation, a very pertinent issue in this kind of device, no single failure shall cause this and the probability of unwanted operation from all sources shall not exceed 10^-5. IMHO that is easily achievable with well known methods.
In fact, the only additional component not part of standard airplane hardware would be the lift/drag polar curve data. I presume any transport category aircraft-certified computer would have error-correcting memory as a standard feature, so no additional reliability issue there. And the software algorithm is very simple.
Furthermore, this suggested device would only need to be armed at final approach and when at or below the glideslope, greatly reducing its potential to do any harm. Last but not least, it would only ever be triggered when a flight critical "10^-9" event has already happened.
To summarize, if industry can build safe stick pushers, building this device is not a problem.
So please tell me if I've forgotten something crucial. And to repeat: this is about the technical feasibility. The actual usefulness of this suggested device is another discussion.
