1. We have a large homgoneous market where you can build a product and it’s expected it can succeed for hundreds of millions of Americans
2. EU is the easiest second market, and another step change of hundreds of millions of customers in a somewhat unified market
3. there’s not an easy 3rd economy that replaces EUs wealth, population, and comfort with English + technology
When we piss everyone off in the EU tech company growth gets kneecapped and limited to US / Canada. Theres not an easy market to expand to without much deeper focus on that specific market and its needs, for much fewer returns.
There's a strong desire to forge closer links with the EU now and reduce dependence on products that could be weaponized against us at any time. Geographic proximity doesn't count for much when it comes to software.
I take a more optimistic stance here. Trump can only live so long, and everybody except basically Trump and John Bolton knows that the majority of his idiotic tariffs (and nonsensical belligerence like pretending NATO control of Greenland doesn't meet all our defense needs) are wealth-destroying on net, as well as wealth-destroying for at least 10x the number of people than they help (many of them I'd say 100-1000x as many). When Trump leaves the stage, those who replace him will either be Democrats sprinting at full speed from all his policies to demonstrate how not-Trump they are, or Republicans who want to grow the economy. Either way, the stupidity in a lot of his policies is a temporary condition.
Note that I'm not saying everyone should give the US a pass or maintain as much economic and defense dependency on the US. But I think it's hyperbolic to make all your long-term plans assuming something as stupid and self-defeating as his worst anti-ally policies are a new normal, because they harm the US at least as much as they harm everyone else, and everyone but those two knows this.
Now that we're always going to be four years or less from the next potential bout of American insanity, it's time to build a new order that is less vulnerable to big powers and more equitable for everyone else. An order in which the rules are applied more consistently and have teeth. That doesn't necessarily mean breaking out the feather quills and having a big shin-dig at Versailles though. It's doing lots of little things that shift our dependence to like-minded middle powers whenever and wherever possible.
e.g. The white house has threatened other countries (including Canada) with tariffs in order to deter regulation or taxation of american software giants in non-U.S. jurisdictions. That makes dependence on these companies an exploitable (and already exploited) weakness. This is why governments, like France, want alternatives.