Because GDPR includes provisions for handling US GDPR violators, a lot of security vendors were touting up the idea that if a European fills out a form on your site or gets cookied for any reason, you could be sued.
And similar arguments could be made for why American companies would play nice to the EU.
If your company was unable to comply with GDPR, many wouldn't want business with your company anyway, especially other companies who are trying to comply with it.
Except for military force and incarcerations per capita, the US is lagging behind in almost every statistic compared to China or the EU.