You have to be very self-critical when proposing thought experiments. Typically, they end up having no connection with reality (attempts to make variables independent which really aren't), I'm not sure it's productive to think like this unless you're really super-guarded about your assumptions.

You're assuming a 1% absolute difference could easily exist given equal laws, enforcement, and penalties. If you say you're just asserting that for purposes of the experiment, you still can't say anything because the assertion may well be nonsense.

You're assuming you can tease it apart (e.g. existing laws and enforcement's influence on criminal culture) such that stats are "missing", it's not clear that you can. In fact, evidence (prohibition) more likely says you can't.