When I think about it, I realize everyone is a slave to some contingency or another, and I don't really care about the lesser forms of slavery that exist in this world anymore. This applies to both libertarian anti-tax reasoning and leftist anti-work reasoning.
Yes, or manifest destiny or any of its many manifestations. Osmosis. Prophylaxis. People leave when things are bad, for places they think are better. But movement is much harder now.