I really understand where you are coming from, but that's definitely not the standard I have witnessed so far.
Maybe where I'm working we're more harsh than usual:D because we've got the full package - company laptop, transfering anything work related to personal PC is a no go, at home we must use VPN with 2FA, can't connect unapproved USB devices (including mice, keyboards, phone charging, anything), heavy website moderation, and heavy user-based access moderation for anything, and the company laptops are 100% tracked - you have no privacy on it. Even personal phones have to follow some security measures to keep Slack and authentication app (screen sleep <5min, screen lock is a must, and Slack is password protected).
So the theory is that, once thieves will see you're carrying an Iphone, they won't bother taking it. But why? You're already being mugged, everything that's even remotely valuable will be taken. Why would they let their victims go, just because their valuables are more difficult to flip? "Give me all your valuables - oh wait, that's an iphone, nvm my bad you're free to go" is that the idea here?
And on being less of a target for getting robbed in the first place - you're carrying an expensive af iphone, chances are you can afford to carry a lot of other expensive valuables too. If you're worried about getting robbed, start with not carrying a device that's more expensive than a fridge.
My condolences to everyone who actually had to survive through a robbery. But I doubt it could've been avoided just because your Iphone was currently difficult to sell. People can get robbed regardless of their perceived wealth, it's a happen-stance crime.