If it's 3 years long? No. If your oldest kid is too old people often don't want to go back to having a baby. In what I've seen, families with lots of kids tend to have them fairly close together (2 - 3 years max). The moment your youngest turns 5 and things become easier, people stop wanting to go back to the baby phase (can't blame them).

Anyway, if we're talking about spacing 2 - 3 years apart, that means you're not working at all. At some point people will want to go back to work, and that may mean not having another kid.

I think flexible policies are great, but the long leaves I don't think are super useful. Kids are not some abnormal condition; they need to be integrated into a full life.

This is just my pet theory. I think places with overly long leaves (especially overly long paternity leaves) actually discourage men from wanting more children (And of course it takes two to tango here).