If Lore Harp had said "OK, well, maybe we can make a superior third architecture", then yeah, the dismissal of the first point might be easier to take. But Lore Harp apparently refused to listen to Bob Harp's concerns expressed in (2) because LH apparently felt she knew the market better than BH, despite Bob Harp's advice being rather obviously correct on every factual level.
While I agree with your points, Harp's solution probably would not have helped save the company. He recognized one part of the problem but it looks like he missed the bigger threat: that CPM was on the way out and thus their ability to differentiate themselves, which had been what made them successful, was going away. Even a better architecture would have been useless in the face of the adoption of MS-DOS; since they would have either had to use a customized version that would have limited compatibility with programs or run the generic version and lose much of the benefit of a better architecture. ThePC market had reached that point where standardization was going to result in a few winners and a lot of losers, no matter what companies tried to do to remain viable.
In short, a combination of market forces and poor decisions, across engineering, marketing, and executive leadership, resulted in them becoming one of the many "Whatever happened to..."stories.
In fairness to them, at that time in history it was hard to tell which companies and OS's would succeed. Given IBM's money and clout in the computer world in the market it was a pretty safe thing to bet on whatever they decided to use, but that also meant you would be competing with a company with vastly greater resources and the ability to buy into any market they wanted by cutting sweetheart deals that small companies could not afford to match.