Yes, you can win the game without QL. But you have to spend a lot of time and a self-production is not proftiable enough.
You have to buy many raw materials and semi-finished goods to push your finished-goods output. And so you depend on the goods provided by the market.
But I agree, it is possible...
I considered the case: Gaining high position in highscore AND focus on researching AND spend average time for IT.