In 1950 you could afford a car and house on one income - but that house as much smaller than the typical house today. You also had one car not two, your wife (this was sexist times - men worked, women stayed home) probably didn't even have a drivers license. If she did she couldn't drive anywhere when you were at work unless she drove you to work. (thus door to door salesmen: sell things those housewives need but cannot easily get because their husband is at work. Send both partners to work and suddenly houses get larger and you have two cars.

Note that despite the above, in 1950 women did often have jobs. It wasn't the "ideal" and it was less common (and even less common if you had kids), but plenty of women had jobs.