>If you create a big series of regulations and taxes around drugs - then there will still be a huge secondary, black market.

The experience in places where this has been tried is that the supply in the black market reduces and prices significantly increase. So yes, the evidence is that legalization does a better job of restricting black market access than blanket criminalization.

Note that having a legal market doesn't suddenly mean the police stop busting drugs gangs. What it means is that drugs gangs not only have to face exactly the same law enforcement crackdown they already have, but also have to compete with legal, medically regulated access to drugs. It's a double-whammy for them.