those were the only new releases in january and they're from the Bamco-Square-Capcom trinity that can sell anything anywhere.
Again, Xflop accounts for 10% of their sales and these are massive, worldwide reknown franchises.
Imagine what the smaller stuff does, valkyria, persona, etc. 10% of 100k copies isn't worth it for developers. If it's a big franchise like RE or KH you can justify porting costs, just how the cookie crumbles.
MS needs to work on getting a bigger slice of the pie. exclusives might help (just maybe - console business 101 stupid ass multipl