That wasn't the premise though. The premise was:
- US company A controls the market for idea B
- EU creates GDPR which scares away company A
In that case where there is a proven market demand for idea B you can either compete with company A (which presumably has more resources than you), or enter into a market that company A has willingly forfeited.
I think the second option will have plenty of takers if it turns out that US companies are that scared of GDPR.