Pixar has had some underwhelming marketing campaigns, but Inside Out and Finding Dory both had great marketing and look at how much better they did than any other recent Pixar effort. Dory was for other factors too obviously, but IO definitely owed its OW to the great marketing. TGD and Coco had underwhelming marketing and both had underwhelming OWs. Same goes for Brave, MU, and the Cars sequels to lesser extents. Ratatouille back in the day is another example of when Pixar dropped the ball on marketing and it affected the OW. Pixar doesn't need to rely on effective marketing as much as most studios, especially with sequels, but they definitely still need it.