Higher rents and lost mobility for renters are the inevitable results of today's rapid decline in rental units-a decline that will accelerate throughout the 1980s.

Also "inevitable," in the opinion of Michael Sumichrast, chief economist of the National Association of Home Builders, is a turn by the nation's politicans from "a healthy investment climate, that would encourage apartment construction, to rent controls and restrictions on conversions."

Writing in the current issues of the MGIC Newsletter, Sumichrast says that the country has been losing as much as 2 percent of its rental stock annually and the the erosion between 1973 and 1976 has taken nearly 250,000 rentals off the market. The vacancy rate at the end of the first quarter of 1979 was "a meager 4.8 percent nationally-the lowest on record since World War II."

The acceleration of the decline into the 1980s, Sumichrast added, is attributable to "shifting population age distribution which favors home ownership," as well as trends to conversions to condominium and cooperative ownership, plus a long list of economic problems, market problems and regulatory changes.

Supporting Sumichrast's gloomy predictions was MGIC Newsletter's consulting editor, Edward E. Edwards, who added that "something has happened to the once valid reasons for wanting to rent rather than to own. The majority of American families cannot afford to rent, not because of insufficient income but because home ownerships is so much cheaper."