I'll say one thing about the inciting incident that most definitions forget to mention, and that is the impact of the inciting incident on the protagonist. A good inciting incident causes the protagonist anxiety. The anxiety can be positive or negative, but it is the first high point of anxiety for the protagonist.

But don't some stories throw the protagonist through a roller-coaster of anxiety prior to the inciting incident? Yes, absolutely.

But all stressful events prior to the inciting incident also have some semblance of a routine. The routine causes the protagonist to become accustomed to the stress and tempers their reaction to it. This is the "before" mentioned in the article.

Because the inciting incident is a new experience or new information that breaks the routine, the anxiety hits the protagonist with full force and the stress it causes feels fresh and new.

The protagonist is now in the "after" phase mentioned in the article.

EDIT: do not confuse this for the point-of-no-return aka the disaster. The inciting incident is the first time this type of anxiety hits the character in act I. The point-of-no-return is traditionally the end of act I.