Question is: Where would they collect them from?
Surely Drow wouldnt surender their prisoners armed, just to buy their artefacts back.
And on the other hand, if Illithids would make their own raids for slaves/food ... they wouldnt need Drow supply.
Of course, they don't necessarily need trade, but as above-average intelligent beings, they let others do their dirty work. So why not have Drow as predestined slave hunters procure food for them and the equipment from their own skirmishes they don't need either, so they trade it. The equipment they collect from their own raids, wandering adventurers or their arch enemies the Githyanki.
Of course, the Drow sell their slaves without equipment, they wouldn't be that stupid.
One might as well ask if the Illithids would ever consider any other trade good besides slaves for food. I can't think of what else they could ever need...
