Just saying, there are users who prefer heroin because it lasts longer, you don't have to inject so often. I daresay that there are even those who would prefer some good raw opium.
Those who "want" the fentanyl are often on the supply side because of the money to be made.
You're correct on that. A lot of users prefer it but dealers are all in love with the fentanyl. At the same time many users want heroin but chase the stuff that's laced with fentanyl at the same time. The second they find out someone died from the stuff they flock to the dealer that sold it to them.
CRUSH YOUR ENEMIES! GRIND THEIR BONES INTO DIRT! MAKE THEM REGRET THEY WERE EVER BORN!