What can EU potentially do to you? I have no plans to comply with my website that gets only 5% traffic from EU. I would rather block access to those users based on trade off.
Blocking EU users is a smart business choice to avoid any possible legal issues and far easier than compliance.
https://en.wikipedia.org/wiki/Online_Privacy_Protection_Act
Edit: Apprently, there is a new one on its way: https://eu.usatoday.com/story/tech/talkingtech/2018/06/28/ho...
People like me are the sort who think about Stalin and sigh: "oh, things were so good back then!". That's why we love regulation.
I expect it's more or less the same thing that the US can do to you: Depends on what assets you have now (or may have later) in the EU, whether you ever plan to visit the EU, and what treaties are ratified now (or later, been bitten by this one) by the US and EU countries.
Ignoring the laws of foreign countries is possible if you're willing to put in the resources, it's much cheaper and less risky just to comply. The general idea of being forced (literally or practically) to comply with the regulations of other governments is completely fucked up in my personal opinion[1], but until your government decides to do something about it, there's not much you can do. At least, you get the option to expand in a foreign county market as a consolation prize.
In the end, this is just a comment on some internet board. I'd recommend asking a lawyer that specializes in these matters if you really want to know about the risks involved.
1: I'll state that I'm not against the GDPR in general and think it's introduction is long, long overdue. What I object to is having some foreign entity I have no connection to forcing me to comply to their will. That's a can of worms governments will regret opening.