You should read the OP, Three houses sold over 300K first 6 days in USA.
Oh ok, I thought people were saying it sold almost as much as Awakening in the U.S. ... lifetime, in 6 days. Not just that the opening was better. But now I get it, since Fates is split into 3 Three Houses probably outsold every game except Fates and Awakening in 6 days, and even then it will probably beat those in the next week or two.
With the way Three Houses has fared so far, I can definitely see the game outselling Awakening and Fates (all three versions of the game). With the Switch maintaining great momentum, I can see Three Houses have decent legs, even for a SRPG. Its pretty cool seeing a SRPG gain such success, especially when high-profile SRPGs are not as prominent nowadays, especially compared to the likes of action RPGs.
It's an incredible journey for Fire Emblem as a franchise. After years of being a franchise stuck in Japan, it gained some interest thanks to Smash Bros. Melee, found some success in the West, hit a wall during the Wii/DS days, and finally found great fame in Awakening and Fates (regardless of how you feel about these games in general). And now Three Houses has brought FE to new heights as a successful (commercially and critically) home console SRPG title, the first since Mystery of the Emblem back on the Super Famicom in 1994.
The franchise has truly risen as a B-tier (if not, A-tier) franchise for Nintendo. With the successful mobile game, the TCG, Three Houses, etc., Fire Emblem seems to have a pretty solid future ahead of itself.