Yep, and the legal market prices must not be pushed too high due to excessive regulation and taxation, lest the black markets (and crime associated with them) continue to flourish
Black markets of tax evaders are vastly superior to those avoiding criminal penalties up to life in jail.
When the penalty for drug distribution is a decade in prison which the government then uses as leverage to flip your distributors and then do the same to everyone in your whole organization, it makes it economically viable to use extreme measures to avoid prosecution. Snitches get stitches etc.
Whereas when the consequences of tax evasion are paying what you owe plus penalties and interest, you just pay the money (or go bankrupt). There is no incentive to spend five million dollars to avoid a million dollar penalty as a gesture of loyalty to your people or to keep them from flipping; you just pay the million dollars. There is much less incentive to murder witnesses and risk prison when the alternative was only bankruptcy and not prison to begin with. The violence is primarily attributable to the harshness of the penalties in the War on Drugs and what that justifies in order to avoid them.
Meanwhile prosecuting tax evasion is self-financing whenever tax evasion is prevalent, so it has a natural equilibrium at a low level of tax evasion. Prohibition is the opposite -- the harder you prosecute the higher the street prices get and the more lucrative it is to commit violence to bring in those high prices.
[1]: https://smile.amazon.com/Narconomics-How-Run-Drug-Cartel/dp/...
Alcohol causes tremendous destruction, too, but I thought there was general agreement that national prohibition was worse.
Most people would opt for safer drugs if they had options. As it stands now you are basically at the mercy of the local illegal drug dealer that you know, and most of them don't have high quality standards.