Nintendo has made plenty of core games this gen, from Galaxy 2, to Xenoblade, to TLS, to Zelda, to DKCR, and many others.
What you meant to ask is 'why didn't Nintendo make any 18-rated games for the Wii?', which are two things entirely. Those mentioned games are far more 'core' and 'difficult' than most of the generic FPS' doing the rounds on the HD systems currently, and, as such, sold much better.







