The Southern economy did not simply reproduce the European capitalist-industrial trajectory

This requires careful distinction.

You are proposing something like:

land ownership → mortgage/credit → investment → factories → industrialists

That mechanism can occur.

But the historical trajectory of the post-emancipation American South was not identical to the industrial transformation occurring in parts of Europe.

For example, after emancipation, the Southern economy remained heavily agricultural.

Instead of:

plantation → factory

you frequently get:

plantation/agricultural land → wage labor / tenancy / sharecropping

The distinction is between:

Your proposed model

landowner

→ mortgage/credit

→ industrial investment

→ factory

→ industrial employer

Much of the Southern post-emancipation reality

landowner

→ retains agricultural land

→ hires/rents land to laborers

→ wage labor / tenancy / sharecropping

→ agricultural production continues

So my objection was not:

“Land cannot provide collateral.”

It absolutely can.

And it was not:

“Former slaveholders could not become industrialists.”

Some could.

The problem was the generalization:

slave owners → industrial barons → factories → former slaves become their factory workers

That requires evidence showing that this was a sufficiently widespread and causally connected historical process.