If insurrectional anarchists do avoid substituting themselves for the revolutionary subject, then it ceases to be a question of whether their milieu is ready for an immediate revolution; rather it will be a question of how ready the whole revolutionary populace is for revolution.
So the question becomes: Are billions of people ready for an immediate revolution? Apparently not yet.
From that position, one might come to the conclusion that a large portion of the body of work identified with "insurrectional anarchism" concerns itself with the question of how a small pro-revolutionary milieu can act in ways that simultaneously:
(a) do not substitute themselves for the revolutionary subject;
(b) are immediately implementations of what they understand insurrectional activity to be, even if that activity is not currently widespread;
and (c) may inspire large segments of the population towards insurrection.
This is different from other approaches such as waiting for the revolution, going out and organizing the revolutionary subject towards revolution, substituting oneself for the revolutionary subject, building infrastructure for the revolution, and more.
All of the above analysis of course is premised on certain ideas about revolution, the revolutionary subject, and so on.