Ore trading requires an active participation of miner ship at one point. Then there's most likely PoB involved that is being supplied by others. And only then a trader can buy the ore to make great profit/time. So that is many layers of activity involved.
Smuggling on the other hand can be done at any time due to contraband being available at all times. Making it more profitable or at least equal to mining would make it best thing to trade and we would see a lot of ships around with contraband testing the patience of police while combat-docking on planets thus breaking rules over and over again. ( History lesson - cardamine buff event and junkers )
Smuggling contraband is ~50% more profitable than regular trading. It's already rather good.