I think people don't like to acknowledge shops. If they did they would probably play it and be less biased against the archetype.
I also think that it's also about salience. When PO wins a tournament, it's a more salient and prominent accomplishment. When Shops wins a tournament, I suppose that is "as expected," and fades into the background, narratively speaking.
I try to keep myself honest when evaluating what is actually the 'best deck,' by hewing to the facts. True, those facts can be arranged in different configurations depending on criteria, but I think a holistic POV shows that Shops, not PO, was really the best deck of 2018.