You can't prove that you wouldn't be able to advertise as much without adtech in its current form because 1. since the 90s the internet happened and 2. nobody ever did research into an approach which would serve society better. Which tells me that these smart people are after the money, and not in pursuit of a service that actually helps society.

For example: a simple switch on my browser to turn on/off all ads would be much more consumer friendly, and would still allow consumers to find products if/when they wish to find them. And this is just a simple example that just popped into my head.