I think you're forgetting that there are dreamers, crazies and malcontents that historically have been more than willing to risk everything to make a go somewhere new or get away from their civilized peers.

Persecution is certainly one motivator, but hardly the only one. Some people are driven to explore, some are religious nuts looking for whatever they look for, some just hate civilization or people or their family or whatever, some can't explain their motives.

Civilization isn't for everyone.

Just because there are people willing to risk more doesn't change the fact that you can do almost the same thing today and risk less. All most westerners would need is a few thousand dollars, a passport, and a few weeks time and they can make it to almost any land in the world. There might not be any free land to claim and start your own country, but even in the US there are still large swaths of ungoverned land that an off the grid type could set up to live their life in peace with little interference from civilization.

These debates always end up with people talking past each other. One side will say that present living conditions are better than they ever were in the past. The other will say that past frontiers provided freedoms and opportunities that aren't available today. Both these things are true -- you are talking about different things.