Mortgages are cheaper today than they’ve been in a half-century. If only most people had the job security, the credit score and the cash to qualify.

The average rate for a 30-year fixed loan sank to 4.69 percent this week, beating the low set in December and down from 4.75 percent last week, Freddie Mac said Thursday. Rates for 15-year and five-year mortgages also hit lows.