For headsets, there are several properties that segment the market:
1. Tracking: outside cameras/emitters vs inside-out tracking
2. Tethered vs wireless (including PC powered, but using wireless transmission)
3. PC powered vs standalone device
For each of these, there are multiple vendors to choose from, except for standalone devices. In this case, the Oculus Quest is unique. There's no other competition.
Moreover, the Quest is the only device that can be run without a corresponding high end PC. If you don't have a PC like that, then the cost is prohibitive. There's also the space factor. VR needs space, which is already an issue. With the PC powered headsets, you also need that PC to be close enough to your open VR space. Otherwise, you need to rearrange your living space or invest in a VR dedicated PC.
In summary, the Vive Index is fantastic and arguably the best headset in the market right now, but the Oculus Quest fills a different niche of that market.
(And as to the topic of the article: I'm done with Oculus based on Facebook's policies).