Th problem lies with not what you could, but what you should put on a phone. These you called game changers are only great in theory/pictures, but not in reality.
A fully glass phone offers little to no real purpose, as well as way too many disadvantages. You will basically see light from behind the phone which would hinder your ability to read whatevers on the screen itself for no good reason. Not to mention there must be some parts of non transparent material on the phone to accomodate batterys, ports and what not. Even if it is techonologically possible i cant think use of it for vast majority of users.
Making your phone thin as paper shares similar problems with the glass scenrio. No one has any use for a foldable paper thin phone, and neither would physics allow it unless we have mutliple breakthroughs with all aspects of technology, for a feature who one is asking for.
Projector is also almost useless, with other drawbacks. However its current technologically possible. Can you tell me any practical use for this feature though?
It is not your fault for wanting a phone like the ones you suggested. Internet and movies seem to portray these holographic and transparent screens as a easy way to demonstrate a futuristic look without thinking about the actual practicality of them.
The next breakthrough for phones, as I see it, is not on hardware. It will be software. And it is AI. And it wont be just applied to your phone, but everything in your life. Once a consumer level AI can understand and perform whatever you ask them to do, then that would be the biggest breakthrough of humanity of the last hundred years.
