Indeed, we are very different cultures. US and many many European cultural differences. A great suggestion for a way forward brought Ross Jackson in his Gaia presentation where he sees possibility for change at national level some countries more likely to form a Gaia coalition, e.g. those who are not part of WTO, EU etc. since those are huge inhibitors of sustainability.
I believe in other countries like US, France, Spain, Italy, local change makers are key! Thus while I would agree with Ross and insist on forming a national coalition of Gaia states, I would see grassroots and local/regional movements in the more resistant cultures pivotal.
This is a million dollar question but I would also opt for incentivising those who choose to live without offsprings or limiting their family numbers to one offspring. Definitely we must challenge common assumptions even in the West where families believe that since the West has low population growth it is desirable or even a responsibility to have more than one child per family to keep the national interests at check. Many of my peers end up with 3 children which as we know have higher ecological footprint than average 7 children from, lets say, Bangladesh or India.
So population myths must be challenged! Lets put together a list of such assumptions in this forum.