~but I would expect for at least thousands to have enough activity to be a hero.~
That's why the merit system was implemented. You now need to actually contribute to the forum rather than just stay logged-in for the requisite time period and spew enough off-topic shitposts to rank up. Again, I don't know what's an acceptable number of members that the community thinks should be ranking up, but as Loyce's data shows 76 members were able to earn enough merit to reach hero.
Now, I don't know what your idea of a "Hero" is, but I've always used the word in an rather exclusive manner. Not to mention "Legendary."