A lot of chemical pathways in your brain, that serve important functions in a healthy person, can be "burned out" by being over-stimulated. Basically, your brain self-adjusts to higher levels of that hormone and you either maintain that level, or you crash hard.
You mention ecstasy. This has actually been studied using that drug. Check it out:
https://pubmed.ncbi.nlm.nih.gov/20420572/
And of course you're familiar with the "rat paradise" experiment. I don't know that anyone has ever fully explained exactly what goes wrong or the rats that causes them to behave the way they do in that experiment. A simple explanation is: they're social animals, but in nature there's a limit to how much socializing they can do. If you give them an unlimited supply, they enjoy the serotonin and dopamine for a while, but eventually they "burn out" and crash, and once that happens they do no socialization at all.
To the extent that these women are
actually asexual (and not just scamming the men while they continue to bang chad - which is probably 50% of the women claiming asexuality), my guess is, their previous experiences on the cock carousel have fucked up their brains. Early on we saw women unable to pair bond. That was apparently stage 1 of this. Now they can't get turned on at all.
BTW, a similar thing can happen to coomers from years of constant HD porn. So, be careful.