Splatoon on Amazon Best Sellers at the moment:
2) Splatoon 2
4) Splatoon 2(DDC)
20) Splatoon Switch Case(¥2,423)
22) Splatoon 2 Girl Amiibo(¥1,880)
26) Splatoon 2 Squid Amiibo(¥1,296)
27) Splatoon 2 Boy Amiibo(¥1,748)
29) Splatoon themed joy cons(¥9,980)
31) Splatoon 2 + Colored ProController + Amibbo set(¥18,425)
57) Splatoon ProController(¥10,500)
73) Splatoon 2 Bundle(¥61,499)
84) Calie & Marie Amiibo Pack(¥2,570)
93) Splatoon 2 Amiibos + Calie/Marie Set(¥10,990)
96) Joy Con Silicon Splatoon cover(¥1,127)
97) Splatoon(Wii U)
This sentence goes against every argument you've had for the rest of the Switch software lineup benefiting from Splatoon 2/increased hardware sales.
The difference between this week and last is negligible at best for all we know other trackers were closer to the actual hw total than MC last week and that's why you see titles dropping rather than going up. I have no doubt there would be people buying Switch + Splatoon 2 with no intention to buy any other game, but we will talk again next week after we finally see a substancial stock of Switches being sold and how it effects BotW, MK8D, Arms and other titles.