Even charlatans can sell stuff and make a ton of money. "Can raise money" or "can trick people into buying" (remarkably similar, really) can not in any way be construed as a validation of a product.
Like you said, Walgreens, a major pharmacy specializing in real medicine, sells homeopathic crap. They also sell very unhealthy food and alcohol. They also sell cigarettes. Not because they believe the product is good, but because that product makes them money.
The best I can tell, once a dev kit is released they still have 3 or 4 years before they will be selling their hardware at a meaningful scale - if everything goes alright. Their burn rate is way too high, guessing by how many people they hired. They will need to have an IPO or they are expecting to raise Uber level funds. Maybe that’s realistic but I wouldn’t bet on it.
neither is possible with no revenue or only dev-kit revenue. you are overlooking the third option: do an ICO.
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.
In fact, if you're at all familiar with con, the best marks are the people who think they'll never be a mark and have a little bit of greed in them.
Usually when people present something that is new an innovative you can understand how they did it. Take for example the new iPhone camera with Face ID. They gave enough details for someone to understand generally how it was done. You can look at the physical pieces of it to see how they did it. Sure Apple may have made some claims that were bending the truth to market it but the technology has applications other than security (animojis for instance). Also, it was an extension of previous technology.
When people do the same analysis with Magic Leap they find that they are outright lying and that they can't actually have anything to backup their claims. Instead they are trying to pass off technology that doesn't have the advantages that they state as something completely different.