I run a small business (scanii.com) and I've noticed over the past year an increasing number of customers leaving us to European competitors, customers that have been happy with us for years, using our European region, but now have concerns over US foreign policy and are giving preferred treatment to EU suppliers. When I asked they said, I'm paraphrasing here, "happy with the product but management wants EU supplier".
What this means in practical terms is that, if the tide doesn't change, US entrepreneurs will have a potential buyer population that is roughly cut in half if they can only sell to US buyers. This will have a cascading negative effect in the number of startups that succeed - impossible to quantify at this point.
Large corps can skirt around this issue by establishing an EU entity and trying to buy goodwill that way but that's not an option easily available to small businesses.
I fear rough waters ahead.