They've already tried banning synthetics. I remember 14 years ago when buying JWH-018 it was sold as "bonsai fertilizer" and then my state banned it by name along with "all other analogues" though I don't know how effective that particular ban was as the people importing/making spice just used different chemicals that weren't explicitly named.
The main draw to this isn't that it's a 3rd rate experience, it's a high that won't show up on drug screens so it was very popular among people on probation back then. Delta 8 still shows up on drug screens but many of the synthetics don't, so if you "can't get caught" but still want to get high people are more likely to reach for research chemicals for the same reason people do krokodil even knowing they will likely have side effects.