And the particular usage of sharecropping in the South was in effect a continuation of the practice of slavery in regards to economics, with the non-landowner forced to work the land under increasing debt for the land owner. Your claim that slavery was on the way out because it was uneconomical is invalidated by the fact that the version of sharecropping that came about in the South after the war kept the landowners on their land and pushed the economic failures onto the sharecroppers. This should be evident in the fact that the economy of the South didn’t actually change from pre- to post-war. Agriculture remained king, particularly cotton and tobacco.
The Jim Crow laws do actually affect economics since they limited what economic activities blacks could actually engage in and their movement to new economic opportunities.
The “new economic opportunities” for blacks (and whites) were in the North, notwithstanding that segregation in the North was perhaps even more rigid than it was in the South.
Sharecropping has no relationship to slavery, though it must be admitted that sharecropping requires less capital investment than did southern slavery. The South lost massive capital from the loss of slaves, oftentimes the loss of land to carpetbaggers, the insolvency of banks, the destruction of infrastructure, and the worthlessness of Confederate money and bonds. It lost a great deal of income from the decreasing prices of its cash crop mainstays. The price of cotton in 1876 was about 1/5 what it was in 1863.
The economy most definitely did change due to the destruction of wealth and loss of income. It probably affected subsistence food producers least of all.
It didn’t take long, either, for cotton to crash. First of all, England’s alternative (and cheaper) source, Egypt, produced the higher quality long-staple cotton. If you look at most of the old cotton land today, it’s either ranchland or woodland. Vast swaths of the cotton producing south was exhausted by just a few years of raising upland cotton.
Certainly, many tried to make cotton work anyway, but it just kept spiraling downward for years, and that’s why so much of the south is now grassland or woodland. Cotton is still raised in very fertile places, (as are corn and soybeans) but the widespread planting of upland cotton is gone.
Nevertheless, agricultural products are still big in the south, though they’re somewhat different and much more “agribusiness” than they were even during the antebellum plantation era.