Well, if you think about it in terms of economics, the O's come in at #19 (according to Forbes in 2017). By this measure, the usual suspects come out on top (Yankees, Red Sox, Cubs, etc.). Since this accounts for gate revenues, merchandise, tv deals, etc., I bet this is a pretty good current guess.
But I bet it also depends on demographics. Guys like me would rank them higher because I saw Ripken, Jr. play when I was a kid, and he was awesome. Pretty much when someone says Orioles, he pops into my head; along with Billy, but that is another thread.
Also, Forbes has Toronto ranked higher. Really Forbes???? Really????