The more we discover humanoid possible ancestors, the more it makes me feel like Homo Sapiens (and possibly Homo Neanderthal) just violently evolved into existence instead of being such a progressive process.
Honestly that may have been the case. We may have been the most physically superior of the homo species, and actively replaced them. Imagine that? What if we weren't the smartest iteration? What if another homo species was actually destined to have a greater evolution of the brain? I'm not even sure if that's how that works, but that is an interesting idea.
It is a very interesting idea - and evolution definitely works that way. If they were smarter but we were more enduring, or if they were smarter but we were just generally more adaptable/adapted to the climate, we would have won. Evolution does not favor the smartest; it favors the one who actually survives.