Sure, the chance is low. But in the current climate people are nervous and it's best not to risk it. The current government has already embarked on a long-term strategy to bring more of critical software infrastructure back in-country, selling the core identity provider software abroad would go directly against current policy.
Trump also already sanctioned Justices from the ICC based in Netherlands because he didn't like them.
He's clearly not the guy with impulse control
Still though, that is about 10 percentage points higher than before Trump took office. Better not to hand him too many tools to exert leverage with.
In the long term, I think this was actually really expensive. People talk and worry about this, and as a result of this (and similar developments) general consensus seems to have shifted towards preferring EU companies over US companies for tech. That used to be the exact opposite for as long as I can remember.
Exactly, that gatekeeper role is what's the difference here. Do you give all data to another country and ask them for pieces back as needed (whenever someone wants to use DigiD, the country can block it), or do you host it yourself and only share the parts that are relevant for this other country's investigations?
Probably a safe assumption, since the Netherlands is a member of the Fourteen Eyes