I hear you. But I think there's a big factor missing here, and it's this: Mortal Kombat is a classically American franchise in a sea of mostly Japanese products.
There's something about this which feels like 'home' and fits in right alongside other American-developed titles like CoD and DotA.
For example, 80k people weren't tuning into the Fatal 8 because of the prize pool -- it was because it was the return of Mortal Kombat; and that's a big deal in 'murica, South America, and Europe. Ed Boon is something of a star here and when he says "hey guys, I'm announcing a new Mortal Kombat, watch this event" the Western world gets excited in a way that's not going to happen for say, Tekken or BlazBlue.
SF is really the only other title that has that sort of impact, and it's because it featured Western-looking characters (sorry Ken and Ryu, but you know it's true
) and had its birth at the height of the American arcade explosion and during the American Karate craze. Marvel features Western comic book characters, so it kind of retains a bit of that as well.
There's a huge amount of potential here, and the only reason it hasn't been unlocked yet is that we've been operating mostly within the FGC (a Capcom-born and based collection of events) rather than outside of it like Smash. But being a Chicago-based non-cartoon FG title is kind of cool and I think it's shown in the interest these games get in the Western world.