You might have a point, but surely the judges of photo contests, galleries, publishers, etc. would all be able to see that he was a hack. No? Is anyone saying Moriyama isn't good ? No is there not room for more than one Japanese photography in your world.
Finally, "committed to self expression" isn't an argument, it's just a reason I think he is cool, and yes I would find those boomers with their 500mm lenses cool if they were taking 2000 pics a day and producing interesting work.