Cropland usage is still lower when looking at the nutrition of it all

I disagree with you and that paper's abstract. They're comparing worst-case current aggriculture with a hypothetical improved horticulture.

Also, I extended my previous post; you might have missed it.

Further, we can plant other crops on that land growing feed crops

How do you intend to kill off the demand for those crops? Or do you intend to forbid people and businesses from consuming crops with a lot of feed-waste like corn or soy?