Rocky IV (1985) is almost certainly the silliest film in the entire series — I say this as one who hasn’t seen Rocky V or Rocky Balboa yet — but with $127.9 million in the till (enough to make it the #3 film of that year, behind only Back to the Future and Rambo: First Blood Part II), it also earned more than any of the others.
In a similar vein, Moonraker (1979) was by far the silliest film in the entire James Bond series, yet it, too, earned more than any of the others — prior to the Pierce Brosnan era (1995-2002), that is, by which point ticket prices had apparently almost doubled. (Of course, if we’re going to adjust for inflation, then the top-grossing James Bond film of all time might still be 1965’s Thunderball.)
I’m almost afraid to look for other examples of this phenomenon.