Anthony, you’re clearly on to something in noting that one of the key aspects of success, historically, with Best Picture winners is some modicum of box-office success. The great William Goldman summed it up best when he likened the Academy Awards to the American automotive industry. Imagine, Goldman posited, that Ford, Chrysler, and GM gathered at the end of each year to hand out prizes to celebrate the best cars in production. How often would they shower praise on a Toyota model? Or on some small, niche model of their own?
If you want to really, really dive into the weeds, the excellent website BoxOfficeMojo.com has all sorts of wonderful indexes, including the numbers for past BP winners and this wonderful all-time index, which even allows you to look at grosses in constant dollars.