From the point of view of role of government in people's lives

My guess has always been that the difference comes about because smaller communities can organize to solve problems without government help, so they lean towards 'limited government'. Larger communities have a naturally harder time organizing, and so they lean towards government programs.

If your community is 1,000 people and 1% of your population is homeless, you probably know the names of all 10 people and figure out a solution case by case. If your community is 10,000,000... that's 100,000 homeless people, which is a wholly different problem.