Well it was a message, right?
Someone you've barely heard of on the other side of the country who you think is small time compared to you has just casually eliminated one of the few things you care about over something as small as a movie role. And he did so in ways that you don't know. Some of your people were bought off or intimidated and obviously he has muscle closer to you than you realized.

Woltz was finally wise enough, after his earlier ego displays, to buckle under. If he didn't he would have been next as this was a matter of honor to Vito. Either Johnny got the part or Woltz got off the planet. That was the message sent and that is what Woltz understood. All Woltz did by his displays was convince Hagen of his poor judgement and that the Familiy needed to move into Hollywood.

I don't think the other families would have cared too much if Vito delayed moving against Woltz. If Woltz had done what you suggested he would have been a dead man, sooner or later, probably sooner.