Resident evil has always sold relatively well on Nintendo consoles with the exception of RE 2 on 64, which sold decently still I guess.
N64(Resident evil 2) - .5 Million
GCN: RE- 1.4M, RE0-1.3M, RE4-1.7M
Wii: REUC- 1.2M, RE4-2M, REDC-0.9M
Those Wii ones sold pretty darn well considering they were light gun spin offs and a port. Not that I want RE6 for Wii U, but this seems like a poor business decision for Capcom (unless RE6 wasn't selling too well in general)