Actually, games have been backwards compatible.  I can play Wii games on the Wii U, and Nintendo (more so than Sony and MS) has maintained a single generation backward compatibility.

That being said, the Switch will not play Wii U disks.  It remains to be seen if the downloads from Wii U are playable on the Switch.

I like that Nintendo innovates on the hardware side, although they clearly don't always get it right.  The Wii U does however get major time/use in our home as a result of Splatoon, Mario Kart, Super Smash Bros., and Zeldas (from prior consoles).  PS3 - not much time at all.