There is a difference between wanting to live alone, and wanting to be "off-grid". It is perfectly possible, as the article itself establishes, to be able to live "off-grid" but not alone. I.E., a small community.

If this is kept in mind, it means it would be possible to build resort-style communities in fantastic/beautiful locations that are fully self-sustainable (for energy, not necessarily food, entertainment, water, etc.).

I could easily see these types of communities being co-op or "hacker communities" run by small private (think YC) companies, that allow for digital nomadic living around the world.

Is it self-sustainable if food/entertainment isn't included? I say yes, because as humans we enjoy a diverse range of food than our own ecosystem anyways. So I don't think importing food is a bad thing. Could you survive off-grid if you stacked up on a bunch of beans in a basement? Yeah, but we want quality of life.

Finally, what if you don't want to be in a community? What if you do want to be alone? Well, that is still possible, it just means that "off-grid" (as the article states) means sometimes running a generator. Not as efficient, but at least it gets you what you want.