If you read most spending reports by companies, they would disagree. SMBs to large businesses all use advertising to increase the reach of their legitimate products. Your local barbershop likely runs Google ads to reach new customers so that he can run his business.
Furthermore, adtech lead to an infusion of capital into the internet, which led to many wonderful things for society. It's easy to paint adtech in a bad light when you only consider the worst things about it, which are being addressed.