[necovek]

Babies, on average, only need multiple feedings a night through the first few months. Even if there was a new baby for one mother every year, that would be multiple feedings only for 3 months out of every 12 months.

Just like parents today, people would power through that, and not make that a habitual sleeping pattern.

I am not saying this makes the hypothesis of the origin being in parenthood true, just that it does not make it false either :)