Maybe a marketing strategy??.... idk why not just have both

Street Fighter will always and forever have more clout than MK.

The short answer is because people are sick of the MK9 glitches and balance problems. I have a ton of design criticisms regarding Injustice, but at least the game works. Despite the balance issues and character-favoring stage mechanics, I know I'm not going to be blown up by 100% combos or have to chase Kabal across the daytime rooftop.

Street Fighter holds strong mostly for two reasons.

1) international competition. The only game that even comes close to having as strong of a global community is Tekken, but Tekken has other problems that hold it back.

2) Updates. Capcom has been rebalancing the game numerous times to keep the community satisfied and willing to practice it. Because of that, people have invested multiple years in the SF4, and aren't willing to throw away all the skill they've honed in the last four years playing it.

Took the words out of my mouth. Maybe if this rumored final patch becomes a reality, tournaments might be more willing to bring it back into the fold.

Man, I hope so. Despite all the praises I gave Injustice above, it isn't as fun as MK. When the game worked, it was the most fun I ever had playing a fighting game. To me, MK9 is like a beautiful ex-girlfriend with a drug problem.

Let's not use that analogy anymore.

Lmao, its too "right on the money" not to.