It kind of works like seatbelts. You can't prove that the fact someone fastened seatbelts had saved one from death in the accident that already happened. Some people survive, some people die. But the relative proportion of those two cases is the matter of scientific studies - that's the first method we have to determine that seatbelts help save lives. Another one is a mix of physics and common sense. It's better not to be ejected from your seat at high velocity and fly through glass. In the same way, it's better when the screen does not hit the ground (as rubber cases are bigger than the phone and thus protect from impact) or hits, but with much smaller velocity (as rubber absorbs the energy from collision with the ground).
So yes, we can't say much from all the anecdotes here. But there are strong reasons to suspect that phone cases are a net win in protecting screens from damage.
> But the relative proportion of those two cases is the matter of scientific studies
I guess my point is that I'd like to see a study like this, and I'd like people to stop saying "My case has saved my phone so many times," because nobody really knows that.
I'd like to know how much and in what situations a case actually is likely to save your phone from meaningful damage. Because, to use the analogy, my phone's been in a bunch of car accidents without its seatbelts -- non-trivial ones -- and is completely fine.
It would be one thing if a case didn't come with the added cost of a bulkier phone (as you mentioned, rubber cases make the phone fatter). But they do, so it's a cost-benefit analysis, and I think we're all mostly guessing. My assertion is just that I think most people are guessing too much on the side in favor of having a case, because iPhones are not as fragile as they seem as long as you treat them with a reasonable amount of care.
> iPhones are not as fragile as they seem as long as you treat them with a reasonable amount of care.
Accidents aren't about reasonable amounts of care. Cases are obviously there to protect phones when placed in non-ideal situations. Your crusade against cases is fairly silly.
So yes, we can't say much from all the anecdotes here. But there are strong reasons to suspect that phone cases are a net win in protecting screens from damage.