"Or you could not click install"
Incorrect. You have to click "later" and then "remind me later" EVERY FUCKING DAY on an Apple device.
On Apple desktop/laptops you have no button for don't install, so have to click the update notification which then loads the updater and then you can click later. EVERY FUCKING DAY.
Not updating an Apple device leads to constant harrassment until you cave in and they "upgrade" you to the new slower version of the software. This leads to frustration about performance which eventually leads to a new device. You're then left with the choice between abusive Apple and evil Google for your new device. Oh well, at least Android devices never get updates...