Presently the best we can say from the data is that men seem to take close to the bare minimum of required time off, so it makes sense to increase that time if the goal is men spending more time with the newborn and/or supporting their partner.
Another conclusion may be that while it it /legally/ acceptable, it is not yet socially acceptable.
Finally, maybe an alternative to that approach would be better. Something like a year where both parents are /required/ to be home taking care of the baby.