Yeah, that's why I added the 'likely' to the statement. There's so much variability in how the phone will land, what it will land on, and what type of protection it has, that it's hard to make a solid overarching statement about screen protectors.
Protecting your phone is a bit like buying insurance. Sure, you can insure yourself for every possible outcome, but is it worth the opportunity cost? You can protect your phone against every possible danger in the world, but is it worth the reduction in aesthetics, usability, size, etc?
I, personally, use a case without a screen protector. I'm willing to give up the aesthetics of the phone and add a little bulk, in order to protect myself against what I consider the majority of dangerous falls. I'm not willing to stick something on top of the screen, which I consider the most important aspect of my smartphone. In all my years of owning smartphones, I've only had 1 screen scratch or break, and that was due to a corner drop.
Such a simple question as "Screen protector, yes or no?" has many levels to it.