It will without a doubt have that effect.
EU citizens are now a liability and simply not worth it. If you are in the EU except yourself to be blocked from large portions of the internet.
On the plus side for the EU, maybe now they'll actually get some internet startups catering to them, since non-EU options are no longer available.
The company that sells the advertising on those sites says non-US traffic dilutes the value of the ads, and I'd get 3-5% higher CPM if I filtered non-US traffic.
I've kept them open until now because I like to check on the sites when I travel, but GDPR might be the incentive I need to pull the plug.
3-5% higher CPM on how many fewer pageviews? In general, filtering out traffic should always make you less money, even as filtering to the most profitable traffic increases how much you make per page view.
If non-US traffic really were losing you money your advertising company could always drop ad requests from non-US traffic.
BBC stuff is likewise blocked.
I find region-based blocks all the time :( , mostly related to IP and copyright.
If that is the the case then it is working as intended. Instead of just ignoring regulation and writing off a small risk of some fixed and difficult to enforce fine as cost of business the "4% of global revenue" clause puts the fear of god into companies.
I really hope that data privacy regulations don't have the unintended side-effect of significantly increasing the geographic balkanization of the web.