we can stop ads, but i don't believe we could stop only targeted ads because then we'd have to prove that they are targeted. that's way to hard except for extreme cases (like the infamous ads for a pregnant girl)

but ads are not the only problem. we'd also need severe, and i mean bankrupting a company severe punishment for data breaches if we want to get companies to keep our data secure.

in a very advanced future where tech is so advanced that anyone can easily scan a planet to get the data they want, punishment for the abuse of data is the only option. but until then, i think we are better off to simply prevent the collection of data in the first place.