I guess parent fears that Google will blanket-disable access to all Google services in the EU, as retaliation. Unlikely imho, but it's true that Analytics was a big loss - it's only one step down from their core product, Adsense, and if GDPR enforcement comes for Adsense then they will have to go nuclear.
Would they really throw the golden egg out with the bathwater though - even if the egg's not shining quite as bright anymore because targeting isn't as accurate? Seems like an overly risky move that stock holders shouldn't allow.