It really depends on the market. The institutional investors are common in the South and Southwest. I think the fact that they exist at all is a problem.

You are correct however that smaller private investors are more common. I live in a small city. Small property management companies from NYC and NJ are pretty commonly buying up 2-4 family houses. I suspect that some of these "small" players aren't small at all, but hiding in a maze of LLCs.

I know a couple of dudes from way back that have leveraged their way to a real estate empire with >2000 homes in the region.