Yes, as was the plan. Anatolia was absolutely necessary where as Italy wasn’t.
And I’m not sure, given the butterflies it’s hard to say how that would change the war with the pechenegs. Maybe they’ll hear about alexios beating Robert and decide he’s too strong and not worth the risk. But I don’t find that to be very likely. Perhaps with his army in better shape Alexios he’ll be able to defeat the pechenegs early on. I don’t know, it’s possible but it’s up to what you believe. Overall I think the lasting effect of a major win at Dyrrhachium is that he can go on the offensive against the Turks a hell of a lot earlier, and either avoid the crusades or at least be in far greater control of it.