"Update everything immediately just in case" is a lot less attractive when you see more downtime from updates breaking things than you do from hackers. Windows updates are an endless source of pain, but now every program seems to demand to be updated practically daily. Even things that you shouldn't have to think about like keyboards, mice, and printers beg to be updated all the time.
Downtime is annoying but workable. You can't unleak customer data after your system gets hacked.