I mean until they start enforcing the law on US companies operating in Europe then yes, EU advertising companies are going to lose out. But that's no different

I mean until they start enforcing the law on US companies operating in Europe then yes, EU advertising companies are going to lose out. But that's no different from any industry where one group of companies just violates the law whenever they feel like it. See Uber, Lyft, etc or the various companies that undercut their competitors by selling unsafe products, or the investment firms that beat the returns of their competitors by being pony schemes or by committing other fraud. The reason EU agencies went bust was because they were competing against the likes of google and Facebook, because those companies could arguably target better (or were perceived to), and they could only do that because they were breaking the law.