>This will seriously cut down on more than just ads, ie fake news and unverified sources.
Why do you think so? I don't see clickbait industry seriously affected. They churn out a ton of crappy content which costs almost nothing to produce (at least if compared with reputable journalistic work), monetize it with low quality ads for shitty CPM rates, but as long as part of their content goes viral, tons and tons of pageviews allow to balance everything.
GDPR changes nothing in this business.