Nothing says GDPR is something that can't be improved upon. Better enforcement, refinement of laws, everything is possible. It has to begin somewhere and that beginning is rarely perfect. Every failure is also an opportunity to learn what to do better. As some other people have commented, the intent is right, the execution has to be improved. Edit: Fixed grammar and some words
The issue is the collateral damage. The EU doesn't have a thriving web/tech sector to begin with when compared to the US or China. These kinds of things likely make it worse.
Nasty social media that makes their money on outrage and exposing people to scam ads? That's about the only thing I can think of, and I don't think it's a big loss. The legal environment of the EU might actually pave the way for better social media, if the market wasn't already monopolized by the current incumbents.
As a counter-argument, Europe and especially the UK has a thriving fintech scene that produces solutions light-years ahead of what's currently in the US, despite the stronger consumer protection laws that we have.