Cool. So I perceive that your posed question earlier was a tad rhetorical.
You nicely expressed an "objection" that is often raised by some folks when we (at LEAP or other drug policy reform orgs) give a public presentation in favor of ending drug Prohibition.
That is - the (hopefully) good intentioned query is offered, "Well if we put the illegal dealers out of the drug business, they'll just GET INTO ANOTHER BUSINESS" (emphasis added to denote the tone of voice)
The implied corrolary is that, "Since they'll just get into another line of business, it's of no value to put them out of the drug business".
When the objection is offered sincerely, it's easy enough to respectfully counter and the inquisitor leaves smarter than when they entered.
When the objection is offered with dismissive disdain (from a stern Prohibitionist), it just sits there and - like every other 'defense' for Prohibition - looks silly.