Sixth, sex dolls can't (yet) be made to convincingly pretend to like you and lie to you about how much of a "stud" you are in bed. Narcs gotta have their narc supply, after all.
Seventh, he can't hurt a sex doll like how he wants to hurt women. Sure, he could hit it and break it (or more likely his deformed hand in the process), but Russhole gets off on demeaning women and forcing them to do things they don't want to do. Remember how he claimed in his book that the prostitute told him she didn't want to be there with him and was being forced to do so, and he openly admitted he gave so little care for her obvious lack of agency and consent that he promptly fucking sued her for not sucking him his penis--even after receiving a refund and servicing from other sex workers at Hof's brothel!