Heroes of Might & Magic III: Horn of the Abyss

Okay, fine. Let's compare the player activity and the number of tournaments on HW for the third and fifth installments. I think that will clarify a lot.

That's a poor comparison. Different audiences play these games. Players have been playing the third installment for years! And not just online. So, the third installment simply has strong traditions that, by definition, cannot exist in the fifth. By the way, in the first year, the fifth installment was very popular, and the turnout was high.