As to your first paragraph, it wasn't an excuse, it was a business decision. There is no doubt the arrow line was more profitable for Piper than the expense of manufacturing the Comanche. Ditto for the Seminole versus the Apache and the Seneca vs the Aztec.
As to your second paragraph, it's not hard to believe, because nobody believes it. Even as an arrow owner as I've said it before, I have yet to hear a single person argue that on a performance, fit, handling or finished basis, the pa-28 line is in any way shape or form superior to the Comanche line. What it was, was cheaper and more profitable, and you have to be biased to argue the comanche is superior on that particular front.
The point of the prior poster was that there were ways to improve the arrow line to close the gap with the comanche benchline without introducing the opportunity cost of comanche manufacturing. But as I remarked earlier, that too was a business decision made in order to not cannibalize sales away from their lance offering. In doing so they ceded the personal HP 4 seater cruiser to beech imo, and the rest is history. That is why I'm looking at 260/285 engine Debbies as replacement for my arrow mission, and not a lycoming equipped airplane like I would prefer. The level of support based on production numbers is simply more favorable, so much so I'm willing to entertain the added cost of craptastic engines like the 520 (though i would probably lean to the 260 hp variant of the 470 as a more desirable engine to own long term). If piper had retracted the Dakota, I'd never utter such a thing. World of what things are vs world of what things should be type of thing.