Sorry, my father in law was not only personally present and a witness to the events - your "anecdotal witness" - he was also a teacher (and high school principal) and a devoted student of history. His conclusions were drawn not only from his personal experience but from years of study and reflection. Because my undergraduate degree was in military history, we spent many hours discussing these issues and reading books together before his untimely death.
The supposed 'many' who saw an easy way out were conspicuous by their silence at the time. The cold (and cold-hearted) analysis from the safe haven of the freedoms that were bought with American blood is what is hopeless here. They did not have the knowledge we do -- they did not have the more refined weapons we do -- they did not have the time that we do.
Plenty of third parties saw the unconditional surrender demand as prolonging the war to little purpose. Few probably knew its important at the close of the war in Europe for keeping all the allies on the same page instead of bickering with one another or negotiating anything with the Germans, and it was useful in that context. It was superfluous with Japan.