Street Fighter hasn't been Capcom's flagship series for some time now. Capcom's own
financial review from October claims it's Monster Hunter.
As for the bigger problems...
According to the same financial review Capcom's profits for 2014 were
down 41.6%. Their current budget for work-in-progress game software for the
entire company is 5,274 million Yen, or roughly
$43 million. Considering the cost of AAA-game development is only increasing with this new generation, I think it's safe to say that Street Fighter V wouldn't be getting made without Sony (or someone else) being involved.