"Inland flood plains are usually narrower, and don’t offer as much land area for farming, which is why all the major ancient civilizations that developed agriculture were centered around deltas and flood plains near coasts (India, China, Mesopotamia, Egypt)."
There are also lots of flood plains and deltas around the Nile river in Egypt and the Tigris and Euphrates in Mesopotamia, the Ohio river valley and the Amazon that are nowhere near the coast.
"There are also lots of flood plains and deltas around the Nile river in Egypt and the Tigris and Euphrates in Mesopotamia, the Ohio river valley and the Amazon that are nowhere near the coast."
Yes, there are flood plains inland, I never said there weren't, but they tend to be narrower and offer less arable land, because rivers converge closer to the sea (and form wide deltas when they dump into the sea), and thus, a wider river/delta = wider flood plain = more arable land.
The major deltas in Egypt and Mesopotamia ARE near the coast, just look at the satellite images (see how the largest green areas, the arable land, is near the coast and tapers inland):
Egypt:
Mesopotamia:
