If you exclude the history of crime in this country and go only from the context of this specific conversation, you have a valid argument.
There are no Mexican cartels. They definitely don't operate in the USA (because they could never operate in a covert way in the USA and a public way in Mexico, being smart and adjusting to fit situational needs). The cartel just sits on the other side of the border and 'hopes' their product makes it to market and hopes they can find random repeat drug smugglers for their BILLION dollar operations.
The mafia was wiped out by the Feds. Vegas is totally clean of corruption.
MCs are just guys that enjoy riding together and having chapters spread throughout the country.
I can't buy illegal drugs in every town in American (which would require a sophisticated multistate/international logistics network). I can't launder money (yet the government continues to impose complex money laundering rules on banks at significant cost to the industry for some reason?). There aren't massage parlors in every city with women from China/Korea, with those women routinely changing out.
And if anything illegal is happening, it just random individuals, acting on their own, who HAPPEN to not get caught. A multi billion dollar international network, that has an uninterrupted supply of drugs/gambling/sex in most ever town in the country, all done by random people that somehow make it come together.