There have been international competitors in key US industries for decades. The most that’s occurred has been bailouts of US heavy industry such as cars. Examples include Toyota, Ericsson, Sony, Hyundai, VW etc.
When there are reciprocal markets between countries with similar approaches to government and law, there isn’t much of a problem. When one country adds tariffs, the other usually just matches them.
Of course but I'm talking about more consumer-facing (and.. 'interactive' in a way car manufacturers aren't) companies, social media, etc.
Closest I can think of are Ocado and Monzo, neither of which (especially the latter) are big enough to compare yet. Perhaps Just Eat (UberEats competitor) too which recently announced US partnership with Amazon. (Veering off-topic here but I've long been surprised that Deliveroo hasn't massively expanded globally? That's the dominant one in London at least, and very quickly ate Just Eat's lunch, which long predated it.)
When there are reciprocal markets between countries with similar approaches to government and law, there isn’t much of a problem. When one country adds tariffs, the other usually just matches them.