The answer to that is 'it depends'. We know certain substances like alcohol and tobacco can be/are addictive and yet the product still sells with warnings.
In the case of alcohol and tobacoo, I do not think these products are engineered for addiction, they are engineered for taste and addiction is a side-effect. If they could be produced to have the same short-term (< a few hours) effects while avoiding the long term effects (addiction), the companies would (hopefully) choose to do that. I do not imagine these companies to build these products in a way that maximises their addiction.
In the case of alcohol and tobacoo, I do not think these products are engineered for addiction, they are engineered for taste and addiction is a side-effect. If they could be produced to have the same short-term (< a few hours) effects while avoiding the long term effects (addiction), the companies would (hopefully) choose to do that. I do not imagine these companies to build these products in a way that maximises their addiction.
social media platforms however, ...