That might be the most realistic solution, ironically. They might end up in the bin of start up death from pre-mature scaling.
I have no doubt that someone is going to win big in AR. Apple can hit the ground running with all of these ARKit apps. Unless Apple really screws something up, they will have the software advantage by a wide margin.
I'm not convinced that either Google's Series B investment in 2014 or Sundar Pichai's board seat indicate that Google believe's Magic Leap has a high probability of success. The series B was now quite a long time ago. Google has had no trouble getting in to the same line of business as their own investments or companies were the CEO sat on the board.
neither is possible with no revenue or only dev-kit revenue. you are overlooking the third option: do an ICO.