Cannabis and hemp are basically the same plant -- yes, one is psychoactive and the other is not, but they share cultivation tools and as far as I know, cannabis can be used in the same way hemp is (although the opposite, of course, is not true). At the moment hemp is locked out of the market because it's too similar to cannabis for authorities to just let people grow it; but once cannabis is legalised, hemp will likely make a big comeback, as cannabis grower will grow both cannabis and hemp, if necessary switching between one and the other at very short notice, especially if the price of cotton rises over the one for psychoactive cannabis. Even without switching actual cultivations, as far as I know, you could sell cannabis as hemp (although the opposite is not true) right away.

> I definitely agree hemp can displace cotton

That's what I'm saying. Hemp is much cheaper and it's been shut out of the market only because cannabis was and the two cannot easily be distinguished. Once they're both legal, things will change.