I think it's close, needing to be tethered to an expensive PC was definitely one of the biggest deal-breakers.
The content is still a little thin I think. It seems like they're positioning it as a gaming console, and while they have some fun games like Beat Saber I don't think they have the depth of content that popular consoles usually have.
I think the other big thing left is the comfort/weight distribution, for me it's not terrible but I think there are other VR devices that are better. If they just get this to a good enough level I think watching 2D media becomes interesting. If a group of people want to watch the same show at the same time and place and own a big TV, it probably won't replace that, but I think there's enough other circumstances where media is consumed for VR to make inroads if it's comfortable enough. The nice thing about that use case is there isn't the same chicken-and-egg software problem that VR has in other areas.
Right now I don't feel this is the product that will take it mainstream because of those issues, especially the content. It's a shame that Oculus wasn't able to make it (optionally) plug in to a PC and has a separate headset for that. I feel like a lot of the current PC-based VR customers will order that by default, where if they made one device that worked in both cases it would bring along more of their existing userbase to mobile. Even primary PC gamers would probably appreciate low-power versions of their games that they could use on the go.
It's still very good for a v1 device though. If they keep addressing the biggest problems more mainstream success (didn't Mark Zuckerberg say his current goal is to sell 10M units?) doesn't seem that far away.