The problem is that the market itself is shrinking (as we speak) as a result of GDPR. There won't be much of a market left to disrupt. Ad targeting got as invasive as it did because that was the only way to make it profitable. The moment that ads stop becoming profitable, advertisers will pull out. This won't be gradual thing for most companies - this will be a next week type of thing. Few companies can afford to light money on fire in the form of ad spend if they can't recoup it. Some ads might still work in the EU, but it will be a dramatically smaller market within a month or two.