I disagree that it’s that much different from people being immersed in their smartphones, not taking notice at all of their surroundings anymore. With a sunglasses-like solution, you probably would/could still see the actual surroundings in your peripheral vision, or via pass-through, similar to how you can still hear your surroundings through non-sealing earphones, or via pass-through for sealed ones.

Very implausible imo, have you used VR before? Will never be safe to use in public spaces: what and who is around you is unpredictable, so only AR will be viable.