Yes, unlawful trading is useless because you are not getting any real compensations for the risks you taken while hauling contraband commodities. You still able to do more or equal amount of cash with lawful trading or mining without big risks. Also smugglers are stuck with using medium transports usually that makes it even less profitable.
I was smuggling a lot in the past because it was interesting, but then i lost interest because my smuggling route was nerfed (Islya artifact price) so it become a way less profitable then just lane corporate trading with with a way more risks to being not only pirated but even destroyed without making demands (hostile parties\factions).