Dude he literally said the game's sold fine. Mat is not paid by publishers to do PR for them, so if the game performed bad in the US ("not good" would suggest it's done badly), he would have said as such or alluded towards it more strongly. It may not be selling as well as VII Remake, but VII Remake is an iteration of the most popular FF game ever made, high bar to clear. XV was a multiplat title from Day 1 and XBO was actually doing pretty well in the U.S relative PS4, so of course NPD results for XV would have been stronger than XVI, which is on only one platform at launch.
I think too many people here, on ResetERA, Installbase, NeoGAF, Twitter etc. just have a weird sales fetish over FF XVI and in 95% of the time it's for console warring. Personally I think your intentions aren't in that realm, just more around wanting an honest picture of the game's sales and to cut down on the people who want to say it's doing phenomenal numbers (which it isn't, though IMO it doesn't need to in order to be a sales success).
That said, I am just maybe curious as to what reasons you feel the game isn't performing well, your own personal thoughts on the game (if any), and what you feel Square-Enix and/or Sony could have done to make the game a bigger seller.