I agree and disagree on Nintendo.Wii:
I don't think sales have changed drastically compared to the Wii, but that is with the caveat that the Switch is still an active platform. Wii had 3 games over 30 million (excluding Wii Sports) and another game not too far behind.
Wii Sports 82m (free bundle with most Wiis)
Mario Kart Wii 37m
Wii Sports Resort 33m
NSMB Wii 30m
Wii Play 28m
Wii Fit 23m
Wii Fit Plus 21m
SSB Brawl 13m
SMG 13m
Wii Party 9m
That's the top 10 for the wii, dominated by one-off "Wii" games. Sales of their franchise games outside of MK Wii and NSMB Wii aren't crazy. Now the Switch top 10:
1. MK8D 29m
2. ACNH 26m
3. SSBU 21m
4. BOTW 20m
5. Pokemon SS 19m
6. SMO 19m
7. Pokemon LGPE 12m
8. Super Mario Party 12m
9. Splatoon 2 11m
10. NSMBU Deluxe 8m
No games above 30m yet, but probably will have two after the next financial report and may well hit 6 20m+ games already. A lot more proper games here, but we're talking about franchise growth. Let's compare Wii to Switch, with the obvious caveat that most of these Switch games are still selling a lot and Switch is only half way through its life and will add a lot of games:
3D Zelda: Wii: Twilight Princess 7.5m, Skyward Sword 3.7m. Switch: Breath of the Wild 19.7m.
3D Mario: Wii: Galaxy 12.8m, Galaxy 2 7.4m. Switch: Odyssey 19.0m
Smash: Wii: Brawl 13.3m. Switch: Ultimate 21.1m
Mario Party: Wii: MP8 8.9m. Switch: SMP 12.1m
Animal Crossing: Wii: City Folk 4.3m. Switch: New Horizons 26.0m (3DS AC was 12.8m for a better comparison)
Mario Kart: Wii 37.3m. Switch: MK8D 29.0m
And I could go on, there's lots of examples. Mario Kart is the only one without a huge uptick, but it will still outsell MKWii by the end, and Wii was the big peak for Nintendo before this. Other franchises have seen massive growth, like Luigi's Mansion (7.8m vs 5.4m from the last game), Pokemon (Sword and Shield are the best selling since GB era), Splatoon is new and huge, Fire Emblem Switch quickly became the biggest FE game, Hyrule Warrios AOC became the biggest warriors game ever the day it launched.
Compared to Wii, Switch games are selling with as big of a jump as PS3 to PS4, compared to WiiU/3DS and Nintendo's average consoles, Switch is in another league. The only thing Switch is missing is a new 2D mario and maybe one more big selling new IP to compare to PS4's new IP success.
So yeah, Sony have done well but I don't think this is just a Sony thing.