It costs money to make games, so why not have someone else make it for you?
But see, it would cost more money to have someone competent make one of their games.
And, since they've said "Platinum Games was unapproachable" for a new DMC game, despite Hideki Kamiya saying he'd be perfectly happy making stuff for them, I imagine it's their massive, throbbing pride and ego that disallows them from trying to contact ex-Capcom staff for help. Which is weird, since Inticreates and Dimps, both of whom have made a bunch of games for them, both supposedly contain ex-Capcom dudes.
But who cares about logic? Those Call of Duty sales beckon with their seductive Western QTE fingers!