Corporations fear things breaking. Retraining is rarely an issue for a browser upgrade. However, if someone pushes out a crap Chrome update like this and an LOB application goes pop then heads roll. Chrome is entirely out of band from their normal operations and skill sets so it just doesn't even get considered. It also has dubious unpredictable support lifecycles and a rate of change which would scare anyone. To use a car analogy: they want a 3 year old Volvo, not a 6 month old Tesla.