How did Helen Levitt survive?

I've been getting more into street photography and picked up a book One, Two, Three More that focuses on Helen Levitt early work in NYC from from 1930s to 1940's.  Pretty intriguing stuff.  Book might not have her best in it, but still very inspiring.  

But as I review her work, and consider other early street photographers work, I'm left with the question on how in the world did survive and pay their bills?  I can't image how they could have.

Any idea how?

If you want a good book here it is -

 https://www.amazon.com/One-Three-More-Helen-Levitt/dp/157687852X

While teaching art classes to children in the mid-1930s, Levitt became intrigued with the transitory chalk drawings that were part of the New York children's street culture of the time. She purchased a Leica camera, the favorite of Cartier-Bresson, and began to photograph these works, as well as the children who made them. The resulting photographs were ultimately published in 1987 as In The Street: chalk drawings and messages, New York City 1938–1948.

She continued taking more street photographs mainly in East Harlem but also in the Garment District and on the Lower East Side, all in Manhattan. During the 1930s to 1940s, the lack of air conditioning meant people were outside more, which invested her in street photography. Her work was first published in the Fortune magazine's July 1939 issue.

Levitt received her first grant in 1946 from the Museum of Modern Art. In 1959 and 1960, she received two grants from Guggenheim Foundation for her pioneering work in color photography. In 1965 she published her first major collection, A Way of Seeing. Much of her work in color from 1959 to 1960 was stolen in a 1970 burglary of her East 12th Street apartment. The remaining photos, and others taken in the following years, can be seen in the 2005 book Slide Show: The Color Photographs of Helen Levitt. However, she felt equally comfortable working with black and white, as she did both in the 1980s. In 1976, she was a Photography Fellow of the National Endowment for the Arts.

From Wikipedia

I seem to recall she an Oscar nominated screen writer and film editor.  So she worked in the film industry.  

OHHH, OK.  Well that makes things  possible.  Many of these street photographers fam really gains momentum after their death.  Which brings greater question on how their economics worked out.  

You can't be a photographer living in NYC and not know Helens work.  But yes, she made her living from the film industry.