it was the marth being stupid he could have upBed or jumped out of the those jab cancels.
Over all I like your video the music is good, good edit, and some surprising follow ups. Some of your opponents suck though, who the hell rolls behind Ike after being jabbed by him? Seriously I've tried that jab to reverse Fsmash about a 100 times and it hasn't worked once.
I'm gonna have to defend this somewhat.
Every opponent has their habits. Some like to roll after getting jabbed multiple times, because instinctively, they "panic" and do what is the easiest thing to get out of that situation. Sometimes it depends on what part of the stage you're on (opponent on the edge, therefore he rolls away from edge). Although you are correct on the fact that smart players would DI or find other means to escape without being punished.
As far as the Marth countering with Dolphin Slash goes, that is one of the most predictable things an Ike player should know going into the match up. You fake jab cancel once, shield the Up-B, and punish. So there is a chance that Sito might have punished or his opponent has been punished by him like that before and didn't bother doing his Up-B.
But like I said, you are right about the DI.