I don't think much changed, really. The contraband and services offered on these marketplaces has always been backed by criminal enterprises. Mostly the markets provided level of indirection that made purchasing palatable and gave a false sense of safety.
Illegal online marketplaces absolutely do reduce "turf wars". It's argueable that there is harm reduction compared to street dealing. Then I suspect it creates new consumers so there is that too.
Ask an actual sex worker what they think about that.
Sure, but the point is about secondary effects. If pimps are "competing" online then they need to compete on, well, marketing and UX. If they compete in real life then it is about who controls physical territory.
There are lots of studies about the unintended consequences of prohibition.
you are either a naive man or a dumb man, unclear which.
Online markets for sex work allowed women to operate far more safely than "the street" allow. I had friends who were affected by the crackdown on craigslist etc.