The product is taxed like crazy but in general taxes are not going up because of pot. Gov meddling in capitalism is of concern. Most of the rest of the fallout you mention is not happening, at least not yet.
I am very libertarian but realize a lot of hype about legalizing weed was simply none sense.
Do the dopers think that it will be legal for 12 or 15 year old kids? Do they really think the cost will go down when cigarettes are are what $5.00s a pack? Marijuana or cocaine are not going to be legal for the people the Cartels target as customers
The only way the Libertarian argument works when legalizing drugs is if you have no socialized medicine. In a really cold, calculated way it could be argued that letting the stoners kill themselves or end up as mumbling schizophrenics living under a bridge is justice. It certainly might become a better deterrent than health class in a secondary school.
Just my thoughts