It would have to do at least 600K in the West in the first 6 months to match Bravely Default there, which seems like a huge ask at that price point.
Then Japan needs 400K as well to keep the game on par overall, otherwise you need even more in the West.
I suspect that was potentially limiting there too, but I still think it compares more favorably to its platform and standards.
Arent consoles games often in the 8000s in Japan?
If Octopath can launch before DQ XI/Tales of/whatever in NA and gets the same attention as BD:FF did it could easily do as well or better on Switch. While starving for games is a meme at this point there is a certain truth to it when it comes to being early enough to niche genres, early JRPGs can do really well if they show up at the right time.