"It is not clear how Apple would overcome the privacy and safety issues that Google faced"
Contrary to Android, Apple is a closed system. For instance, there are no porn apps to iPhone because Apple has banned them. Sure, some people will Jailbreak their glasses, but Apple could make it very hard to do that, much harder than today. One could imagine dedicated hardware that helps here, especially together with downloadable software so Apple can quickly respond to patches that are out in the wild. Today I think Apple see some benefits with Jailbreaked phones, so they don't really go after them as hard as they could.
There could also be some legislation on top of it, you basically have to sign a contract when you buy or boots up the device . Then we can have hardware (jammers) that would block the glasses from filming in certain areas. Also, the younger generation is not bothered as much about being broadcasted 24-7 as the older. People are already filming all the time with their phones and few seem to care.
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I have said it before, if Apple makes the first augmented reality glasses that really works, it could be as big as the iPhone. There shouldn't really be any cap on the amount of research money Apple should put in here. Even if it cost them $10 billion dollars to get two years head start it will be worth it.
Key to succeeding is to have all these. If one is missing, don't bother releasing a product.
- Slim form factor
If they are ugly and heavy, nobody will use them all day and the product will be useless.
- Adequate battery life
They must last at least a day, preferably longer. Perhaps they could be charged wirelessly to make it a less nuisance.
- Useful Apps
People are not interested in gimmicks. There must be at least a handful really useful apps (killer apps if you like) and they should be tightly integrated.
The graphical user interface doesn't have to be advanced with complicated overlay in 3d. It's much more important to keep the weight low (sleek design) and the battery life long. HoloLens, Magic Leap and Metaglasses are all doing it wrong here. For instance, subtitles, translation and teleprompter could be some killer apps, and they need very little graphics, not even color.