It hasn't protected Average Joe anyways. There is malware being actively distributed, today, that uses nothing other than first-party Apple services to attain persistence.
Average Joe has to grow up. Scam websites and scam callers aren't going away, and even scam apps are being approved and distributed on Apple's App Store. On iOS, you have to do your due diligence to avoid being exploited (and even that might not help against some threats).