It's not a surprise that this guy is single. What he does is a modern asceticism.

The most important thing he mentions is resilience. If we could function with 95% electrical connectivity (1-2 hours/day blackout), it would make increasing renewables in the grid much much easier and cost effective.

The rest, well... he may think that he's "off the grid" in Manhattan, but his lifestyle, ascetic as it is, still depends on power. Removing power from Manhattan is chaos. This guy couldn't buy food without cash registers and ATM networks. The trucks that deliver food to him need traffic lights and gas stations. He was still using running water and sanitation pumped with electricity. I don't think his experiment means quite what he thinks it does.

Yeah, I know he said he disconnected from the grid, but I think what he really meant was he was using as little electricity from the grid as he could while still living a somewhat normal life. For all the reasons you mentioned, it's not really possible to disconnect from the grid in Manhattan.
But imagine if a lot of people did what he did. The total electricity needed by society would greatly decrease.

- The total electricity needed by society would greatly decrease.

There is lots of energy use built into the price of everyday things, and residential electricity is only about 40% of the total. It would make a dent

https://www.google.com/url?q=https://www.epa.gov/energy/electricity-customers&sa=U&ved=2ahUKEwj6j8Gu0NP8AhV5SWwGHRUGA7QQFnoECAoQAg&usg=AOvVaw3-7_KxONIap4ZFLYzlPwzK