He has come to the stark realization that there is no way that even he could build a speaker that would make him happy.
He has actually come to the realization that THEY, i.e. the criminal speaker industry, is unable to satisfy his ultra high standards due to their incompetence and low standards.
You are right that he is miserable but only because he has been betrayed by the speaker industry by false grand promises of high sound quality for years and years which were never realized.
He is the epitome of an audiophile yet is victimized by his fellow audiophiles. How ironic.