Because he doesn't use an autotuner? But probably because the Who largely stopped being relevant in the 1980s
He's actually an interesting singer. I wouldn't call him technically proficient. He doesn't have a great range. But there's something to his voice. And he, at least early one, had sort of a sneering or angry quality to it that you would later find in early punk bands, illustrated perhaps best in My Generation and the quoted above Young Man Blues.