Two interesting questions that bounce of this are "how many members does EA have?" (obviously this is somewhat vague) and "how many members would be optimal?" (more members has clear benefits, but it's presumably possible to get too big). From e.g. Facebook group membership and survey responses, it seems like the answer to the first question is somewhere in the 1000-10000 range. I'm not sure what the best points of comparison with regard to the second question are, but the Extinction Rebellion movement, most major British political parties, and Scientology all have significantly more members.