>there's a huge number of sushi restaurants all over New York and a lot of them are not authentically Japanese nor are they owned or operated by Japanese Americans
That's true everywhere in the US. It's very hard to find an authentic Japanese restaurant, and even harder to find one run by actual Japanese people. Usually, "Japanese" restaurants are run by Koreans.
Well... that's one step closer to authentic than a "Japanese" restaurant run by Han Chinese, I guess.
In my town, the authentic Japanese restaurant was next to the Subaru and Mitsubishi/Toyota car dealerships, and was pretty much there just so the auto executives had a reliably Japanese place to eat while visiting. It went out of business.
Japanese people may be the best at making a restaurant authentically Japanese, but Han are (anecdotally) much better at making a Japanese-themed restaurant authentically profitable.
Sure, but the discussion here wasn't profitability, it was authenticity. You're not going to find many authentic Japanese restaurants in America, especially outside of major cities which have enough Japanese people to support them. I have a Japanese girlfriend, and for her it's a big deal to go to an authentic Japanese restaurant; some "Japanese-themed" restaurant run by Chinese people isn't of much interest to her, she'd probably rather go for a burger than that. (Luckily, she likes burgers too, as long as they're good.)
That's true everywhere in the US. It's very hard to find an authentic Japanese restaurant, and even harder to find one run by actual Japanese people. Usually, "Japanese" restaurants are run by Koreans.