There's always someone who wants something else, whose going to be upset. As much as it may displease others, if you don't have the bread and butter properties, so to say, companies wouldn't have the revenue necessary to do things from lesser selling properties. Given the small percentage of RE games that collect 1/6, I bet an even smaller percentage of AC fans collection toys at all. It doesn't seem like that's the games fanbase after all.
Yes your right. They know they got the consumers for the RE products, but they can only really release the main protagonists of each AC. Why buy the license for one game and release one figure. There are plenty of RE characters that were and can be made. In RE6 alone you got 7 figures that would sell very well.