Depends on the culture which itself will modulate for factors such as access to women, the extent to which patriarchal norms are imbricated into society at large and whether the norms and values are calibrated so as to promote female subservience to male dominance. Due to the moral degeneracy, promiscuity and sexual licentiousness of the West, I would think that the numbers of incel men in places like the US, UK and France would be relatively low (1-2%). You could try and run some crude extrapolations if we knew how many registered users are on this website though even then, the calculus would be contaminated by what I'm sure is a large population of fakecels and infiltrators. Even assuming a low ball number of 1% of the male population however, if we could mobilize our Brothers in Arms in some sort of cohesive, organized movement with clearly established objectives and a mission, we could be as much of a force for change as Jihadists have been on behalf of Islam.