For starters, the economic downturn could worsen or last longer than expected, further eroding incomes. Also, it may be that policy makers and the market do not take advantage of stabilizing conditions to prepare for long-term affordability--a key factor in this analysis, NLICH analyst and report co-author Danilo Pelletiere, tells GlobeSt.com.

"Home prices have been falling and rents have remained stable, so it is not surprising that the two are on track to converge and we will be back--in terms of affordability--to where we were before the bubble."

However, "if the economy doesn't recover in the next four years the ability of folks to gain equity will be severely curtailed. We need to seize this opportunity to boost wages and use programs like the National Housing Trust Fund to lock in affordability for housing."