> A big part is likely just normalizing that it is okay not to have kids
Maybe, but I'm hesitant to say that's a solution, because it implies that we can or should offset the problem (as much as we can assume there is one) by asking some people to have no kids while others continue to have many. It's not a bad thing to do, but it's not really a solution.
> There is also significant government incentive for a population to grow both for the economy and for retirement programs like Social Security.
To some degree, this is a chicken and egg and/or catch-22 problem. Our economy is based on growth, because growth was seen as inevitable, and since our economy is based on growth, we incentivize growth. That works until growth becomes constrained, and then it doesn't. Whether from outside or inside forces, understanding and possible moving towards an economy that is less coupled to growth is an important thing for us to study for the future (even if it only helps us understand our current economy better in the end).
> I do think the best thing we can do is live by example. We can choose not to have kids.
That's not the correct example. If everyone followed the example, the human race would cease to exist. Leading by example should be leading by what we expect people to do. That means leading by some people not having kids, and some people having a sustainable amount. That's not exactly different than it looks like right now if you consider some people to be leading by example, and it doesn't seem to actually do much (but population growth greatly falls off with industrialization and coming out of poverty, so maybe it does?)