The SF producer himself said he hasn't been given a budget for SFV.
From Capcom's side, their reasoning was because of the disappointing sales of recent major titles, like for example this game and RE6. So I would totally understand if they put their failing series on hold, but SFIV was by no means a failure!
So again, why do the SF fans have to suffer? --- HADOKEN! HADOKEN! HADOKEN! SHINKU... HADOKEN!