If they aren't tech savvy, they're dependent on tech savvy people to show them this option and educate them. Even then, they may ignore it. I've seen many people using Android where they just get APK files from somewhere and pass it on tho "friends" (in quotes because this is indeed a large circle of acquaintances and several degrees of separation). It's probably luck that more Android users aren't being hit with malware around the world.
The digital divide between those who can afford an iPhone and those who cannot is glaring on the security front. One of the ways this could get better is for Apple to introduce truly low priced phones (no, the iPhone SE is still quite expensive in developing countries). That's probably as much a pipe dream as getting Android manufacturers to care for their customers.
