the real problem comes down to the size of the community. people play the current top games (sf4 and mvc3) because they have a large player base and it is easy to quickly find a match online that does not have a terrible connection. i know that i played mvc3 over sf3 despite the fact that sf3 is my #1 favorite game because it took me forever to actually get a match that was playable in sf3. people want to play the game that is popular, go to any tournament, there will be huge sf4 and mvc3 brackets and maybe a small round robin for any other game being played.
the community groups together, sf4 was the first new game in a loooong time and played off of steet fighter fame, so it easily attracted tons of people. mvc3 did the same thing, name recognition. after name recognition got the player base set up, people dont leave because they know that they will be able to find games because its where the people are.
skullgirls have a double wammy of having no name recognition and not having the comfort zone of a large player base.
i really hope it does well, but i think it will be a struggle. maybe after it gets featured on some tournament stream it will pick up but i dont know how many people other than the posters on this and dustloops sg boards will actually buy the game at release.