A new report from Bloomberg's Mark Gurman sheds some interesting light on the history of Apple's head-mounted display development efforts.

Citing "people familiar with the seven-year process," Gurman's report said Apple CEO Tim Cook initially "firmly favored augmented reality, preferably in the form of lightweight glasses.". But Apple engineers discovered early on in the project that "making AR glasses that are powerful enough and useful enough is not feasible," and they decided, among other challenges, that they would somehow have to deliver iPhone performance with one-tenth of the power.

Despite this awareness, the report says Apple's AR/VR team, known as the Technology Development Group (TDG), "continues to describe its work as laying the groundwork for AR glasses" to secure resources, 90 percent of which will go into the development of the headset Apple is expected to unveil next month.

The report also referred to "one person on the project", describing a "running joke that engineers were working on the hopeless N421 [AR glasses project] just to keep Cook happy". Despite "very little progress" in developing AR glasses by the end of 2019, TDG's head Mike Rockwell reportedly told hundreds of employees that Apple "could launch glasses a year after it starts selling its first headset."

In January, Gurman reported that Apple had indefinitely delayed the launch of AR glasses to shift its full focus to upcoming headphones and work on a more affordable model. The Information's Wayne Ma reports that the price of the cheaper headphones could be "about the same as the price of an iPhone."

However, the launch of AR glasses is still a distant long-term goal for Apple, which could one day eventually replace the iPhone.