hard to believe that the mansions were so quickly abandoned, and reused by anyone that could figure out something to do with them, but, I never would have guessed that one would become a junkyard

I am not familiar with the the history of the industry of cotton and tobaaco, but I guess it was predicated on slave labor, and no one had a clue how to farm in the south to grow vegetable crops, like everyone everywhere else on the planet, to keep plantations in business with farming instead of bankrupt without slave labor. Or corn, wheat, alfalfa, etc

Then again, this photo is in 1936, after the great depression, and about 50 years after the civil war, this Antebellum mansion/plantation could have failed and been abandoned for other reasons

https://www.shorpy.com/node/26904?size=_original#caption

the same place in 2011:

It was built in 1837 on a 350-acre plantation, with the columns and Italianate tower added just before the Civil War. Dr. Drish died there in 1867, his wife Sarah in 1884. 

It was the Jemison School from 1906 to 1925. After its time as an auto parts warehouse and Walker Evans's visit, it was purchased by Southside Baptist Church, which built a brick sanctuary on one side.

 Threatened with demolition, it was leased to the Heritage Commission of Tuscaloosa County in 1994, and after designation as a "place in peril," acquired by the Tuscaloosa Preservation Society in 2007. It was finally renovated starting in 2012 and opened in 2016 as a venue for weddings and other special events.