The issue is it is difficult, if not almost impossible for one to find a pre workout, with 3-5 grams of creatine, enough stimulant/not over stimmed and other ingredients such as CM, TMG, agmatine, etc all at effective doses as well. Lets say a product has 3-5 grams of creatine, but only 150 mg of caffeine and one needs a higher stim product, they would need two scoops and there would be too much creatine. On the other hand, if said product has 3-5 grams of creatine, but 300 mg of caffeine and one needs a half serving due to the high caffeine content, creatine would be underdosed.
I think too often companies try to make a kitchen sink product, but often fail. The price point would be way to high if everything in a kitchen sink product was dosed accordingly. I would not mind spending the money and educated consumers probably wouldn't mind either. However, the general public make up most of the sales and would be scared away by a high price tag.