There are two types of existential crisis. One makes a person extremely corrupted, harmful to themselves and others. The second type of existential crisis leads a person to a spiritual opening. The second type of existential crisis is a very rare event in the human world, that's why there are very few people in the world who are interested to walk in the path of the dhamma.
In the modern world I think that the most people experiences existantial crisis, that's why when you look to the news you'll see many horrible things are happening daily all around the world. The wrong beliefs, ideas and modern age's advanced technology's effect on the human mind leads people to be "living deads". But the existantial crisis of the most of the humans don't lead them to the dhamma because most people are clinging to collective culture, wrong ideas and beliefs. So they continue the normal way of living with clinging to collective culture, wrong beliefs and ideas even more. People try to suppress their sufferings with using different kinds of tools, but this suppressing only makes them worse.
The important thing is to be disloyal to the collective culture, wrong beliefs and ideas in order to the start on the path of dhamma. You experience existantial crisis or not doesn't matter, but understanding the suffering aspect of the collective culture, society, beliefs, ideas and becoming at least a little bit detached from them is absolutely necessary in order to start the path.
For the ordinary people existantial crisis makes their heart more stiff, makes them more worldling. In the spiritual path the person also have these "existantial crisis" time to time but these experiences makes the person's heart open more to the nature of reality. As a result, the person gradually disidentifes from the collective humanity's insanity and eventually enters to the stream of enlightenment and after the purification and disidentification reaches to a point these existantial crisis periods ends and what remains is only very deep peace, happiness, contentment. So existantial crisis actually helps the spiritual people to walk in the direction of non-self and freedom from suffering. Because mindfulness of suffering eventually leads to complete freedom from suffering. As Thich Nhat Hanh said "Suffering and happiness is one". But for the beginners being "disloyal" to the collective culture, society, beliefs and ideas is the main necessity for starting to the path of the dhamma.