There's already people kinda living like this. Fentanyl is abused because of the intense euphoria the users experience. As tech improves the downsides will go away and the highs will get even more powerful.
I am not an expert on drugs but my impression is that heroin, fent is just really cheap and easy to transport bc it’s so powerful it is so powerful it mostly knocks you out and causes intense withdrawal. It’s not a fun time its a cheap fix for heroin withdrawal that makes things worse. My understanding is that when heroin prices went up (in part because america stopped subsidizing production in afghanistan after 2021) ppl started switching to fent.
I know nothing about fentanyl honestly, but my impression from heroin users at least is that it really is that good, and issues like addiction and withdrawal are somewhat overblown - many occasional users completely avoid them.