Lol imagine using scalpers as the reason why people are not buying games.
Even if we included scalpers and digital only console into the equation it's still low physical software numbers for DeS and Spider-Man MM.
Top 5 Switch game after 4 weeks(Famitsu)
1. [NSW] The Legend of Zelda: Breath of the Wild - 307.621
2. [NSW] 1-2-Switch - 138.790
3. [NSW] Super Bomberman R - 63.149
4. [NSW] Dragon Quest Heroes I & II for Nintendo Switch - 39.244
5. [NSW] Puyo Puyo Tetris - 24.143
The most logical answer is those games are too niche for japanese audience.