The reason it didn’t every become law was because the south had already begun fighting
It was an effort to prevent that. It didn’t work
That is not correct. The amendment passed both houses of Congress (by a 3/4ths majority) in early March. Five (5) Northern states did ratify it, and William Seward, who was the Senator from New York and former governor of New York, said he could guarantee the amendment would pass in New York. He was also the lead proponent to pass the amendment in the US Senate. He was also at that time, Lincoln's nominee for Secretary of State. He was working for Lincoln when he pushed the Amendment.
Lincoln personally wrote letters to the governors of all the states, including the ones that had already seceded informing them of the passage of the Corwin amendment in the Congress. This role by the president is *NOT REQUIRED* in the Amendment process. Lincoln did it because he thought it would help get the amendment passed. He was hoping it would induce the Southern states to ratify it and return to the Union.
It was an effort to prevent that.
I was an effort to prevent the massive loss of money that would be the result of the Southern states becoming independent of Washington DC's control. They had jiggered the laws so that the Southern states were paying for 72% of all the nation's taxes, and the people in DC and the Industrialists in the North liked it that way.
The money was being used to build up canals and railroads in the north and to pay subsidies to Northern fishing industries, shipping industries and so forth. It was all a big corruption gig. It was just a smaller version of the same sort of big government corruption schemes we have going on now.
It didn’t work
The South didn't go for it because remaining under DC control kept in place the system that had most of their money going into New York and DC pockets. They wanted to keep the money they made from Trade with Europe.