It seems highly unlikely, but it would be a major blow to MS. Street fighter is a much bigger franchise than KI. The impression I get the trailer is that it has something to do with an older game for some reason. Maybe a remake of an older sf title?
Theres Soul Calibur, Tekken, Smash Bros., Dead or Alive, and Street Fighter all about 10 tiers above what the new Killer Instinct is as a fighter. I don't think anyone is going to answer to the new KI...unless....Bloody Roar?
"Times are gone for honest men and sometimes far too long for snakes"