How does your iPhone perform when using a deliberate scan tool like TagInfo where it puts up the scan pop-up? It sounds like you’re just talking about background scanning… which seems to be designed to be extremely low power to save on battery… which makes sense, that’s Apple’s approach to power management for pretty much everything… manage the hell out of it. I get that though… you wouldn’t want to be wasting a lot of power scanning for NFC tags on the phone is being used when there is a 0.00001% chance somebody actually is going to be presenting an NFC tag.