Low tier is traditionally investor-owned. Before the bubble, renters accounted for 60% to 80% of residents in places like Logan Heights, National City, central Escondido. During the bubble, homeownership rate rose because some of these residents briefly became homeowners, and now things are returning back to normal.
Even at 20% U-6 unemployment, there are still enough jobs and enough fence-sitters left to absorb middle and high tier inventory.