One reason is that with hololens / magic leap you can’t create black. The display is like a ‘screen’ layer in photoshop and can only add additional light, so you can’t get great contrast and anything you add to the scene has a ghost-like quality.

All those demos you’ve seen of AR glasses making screens on a wall are faked. Magic leap paid a special effects house to make a lot of their ‘real’ demos.

Also - field of view. Magic leap has an AWFUL field of view.