Regarding “bait and switch” of original crew from Japan to a local one, it wasn’t a downhill alert for me when I tried Marugame Monzo in Little Tokyo over a year after it first opened.
I had a counter seat and instead of seeing a Japanese person making the udon noodles, it was an extremely muscular Latin American cook rolling out the dough. I was initially surprised, but decided to consciously check my bias at the door and reminded myself I’m here for a decent meal, not a Disneyland show.
The udon noodles were very good in terms of taste and texture and that’s really all that mattered in the end.
Profit-wise, I don’t think it makes fiscal sense to fly in too many staff from Japan for a fast casual business (pre-COVID, Japanese could visit the US for up to 90 days without a visa), or to do a nationwide search to recruit Japanese staff already living in the US, but for baller places like Tempura Endo, Ima, and Yazawa, etc. I wouldn’t be surprised if a chef or two were flown in long term.