> For dealers this would mean almost nothing when the punishment for dealing already lead people to do things like get in shootouts with police.
I think you're getting at something valid, but it isn't quite what you think.
The punishment for dealing drugs is, as I understand it, mostly applied to major distributors. In this sense, selling drugs wasn't a crime before anyway.
If you're too low-level for prosecution to be much of a concern, it doesn't take much to guide you away from fundamentally similar crimes where prosecution is a real concern.
For dealers this would mean almost nothing when the punishment for dealing already lead people to do things like get in shootouts with police.
Meanwhile legalization of some drugs has directly shown that it decreases youth usage.