A new survey from Zillow  finds real estate and investment experts are divided on the likely culprits behind affordability concerns in the market.
In a survey of 106 economists, real estate experts, and investment and market strategists , Zillow found a slight majority—28 percent—pinned the most blame for declining affordability on stagnant income growth across the country, even as the rest of the economy has moved in a generally positive direction.
At the same time, the number of respondents pointing to "abnormally high rates of home price and rent appreciation" as the main problem was only slightly smaller at 27 percent.
The third most commonly cited answer, following close with 21 percent of responses, was the "abnormally low supply of homes currently available for sale or rent" due to a lack of sellers coming into the market and low rates of new home construction .
Still, given the host of issues hampering the housing market, "one could probably make the case that things could, and maybe should, be a lot worse," said Dr. Stan Humphries, chief economist for Zillow, noting that tight credit also presents a problem of its own.
"We're certainly in a better spot than we were just a couple years ago, but the housing market remains far from anyone's definition of 'normal,'" Humphries said. "It will take years for these issues to either be adequately addressed through policy, or to naturally work themselves out of the market."
While affordability conditions are still generally favorable  as a result of historically low mortgage rates, cost is becoming a more serious problem for homebuyers in a number of metros, including some of California's largest markets, Zillow reported in a recent study.
The survey also turned up concerns about price growth inflating a new bubble if it continues at such a high pace. Those who say price spikes are the root behind affordability problems were most likely to express worries of a bubble, with 90 percent saying there is moderate to high risk—if one isn't already inflating.
On average, panelists in the survey forecast nationwide home value appreciation of 4.4 percent through the end of 2014, nearly a point above the historical average of 3.6 percent. Growth next year is expected to fall to 3.8 percent, dropping again in 2016 to 3.4 percent.
Predictions ranged from a low of 3.2 percent this year to a high of 5.8 percent.
"After narrowing over the past year, in this quarter, the spread between the forecasts of the most optimistic and pessimistic groups not only expanded, but widened by a degree we have not seen in the four-year history of this survey," said Terry Loebs, founder of Pulsenomics, which conducts the quarterly survey for Zillow. "Time will tell whether Washington's unfolding plan to expand mortgage credit will have a durable, positive impact on home values, housing confidence, and market expectations."