Tucked improbably in an article about the rise and fall of the ranch house is a handy "things are getting better all the time" metric:
Housing has always been governed by a simple rule: As people become richer, they spend more money on their homes…. Spending more money has usually meant making the home bigger. This happened in Renaissance Italy, 17th-century Holland, and 19th-century England. It also happened in the prosperous second half of the 20th century in the United States. Some statistics: In 1950 the median size of a new house was 800 square feet; by 1970 this had increased to 1,300; 20 years later it had grown to 1,900; and in 2003 it stood at 2,100. More than one-third of new houses built today exceed 2,400 square feet.
For more in this vein, check out Cato's It's Getting Better All the Time.
Extra bonus update from the Reason vaults: For even more in this vein, check out this or especially this (which mentions increasing square footage of homes as a leading indicator that "the good old days are now.")