Not even close. Fates with multiple SKUs counted reached 3 million. JRPGs are not some explosive genre either. Your 5 million estimate is not remotely based in reality but wishful projection.
The Kirby GB game sold around 1.7 million in Japan alone, probably shipped closer to 2 million. Kirby on SW is not replicating that and like I said, exceptional legs would be needed.
Yes, I do pay attention to sales stats.
Ok sure
Kirby sold over 5 million worldwide whereas you said it was never even close to 3 million previously.
Fates sold near 3 million and since has expanded its mindshare thanks to the mobile game that has been a huge hit.
Switch entries that have or are going to set record franchise sales - Zelda / 3D Mario / Mario Tennis / Smash Bros......etc etc
Lots of franchises on Switch are seeing massive growth and record breaking sales but you think Fire Emblem won't? Why? Its on an upward sales trajectory and had a massive mobile hit - you think sales are what going to decline? Would love to hear your reasoning why 5 million is so ludicrous a suggestion