And would it be too much to ask for Apple to actually test their updates before they push them out?
L
They are tested, extensively. And they go through multiple public Beta testing too. But even that does not catch everything that can go wrong with the multitude of possible combinations of app combinations that are in the wild that can cause some unknown problem until it is the hands of millions of users with those combinations.
The fact is that 99.999% of iPhone users had ZERO problems with that update. You were in the 0.001% that had a problem and a subset of those user experienced something that caused a catastrophic failure. . . but when there are 1.2 BILLION iPhone users in the wild, even that small of percentage results in 1,200,000 users with a problem of some kind. Apple has to figure out exactly what is causing those small percentage of users that issue.
Public beta testers total about 200,000 to 250,000 iPhone users with all kinds of iPhones. . . Your three year old iPhone 6 was probably being tested by maybe 10,000 to 15,000 beta testers. . . but your mix of software? Probably no one. It only takes ONE misbehaving app to cause the problem.
Frankly, it could even be an Apple App that is broken only on your iPhone. Or it could take some specific combination of an App and a specific supplier's bad run of components. That was discovered in a run of iPhone 6s last year with a security update that caused problems with WIFI connections. The problem was a run of just slightly out of spec Qualcomm WIFI radios that worked fine with the original specced software but an update tightened the ranges . . . and then the WIFIs kept dropping connection due to the tighter specs because the radios were too "wobbly" on what they would do.
The fix was to have the software recognize that particular version of the radio and loosen the specs for those particular iPhones that had that run of Qualcomm radio in them. Problem solved for those users. . . but ALL iPhones of that model had to have the update so that all of those radios could be caught and fixed. It could ONLY be found when the update had been released into the wild.