okami on Wii was a cheap port not a sequel. Yes unexpected thing can happen but not a poorly selling game aka Conduit 2 getting a sequel.
ITT: Okamiden doesn't exist.
Also, Conduit 2 sold way more than Okami, and way more than Fallout 1 & 2 combined.
Your point is just invalid. Okami is a lower budget game and they ported for more money it got a port because it does not cost much to port. fallout 1 & 2 sold poorly and gets a sequel because they were cheaper games to make. Fallout 3 had more success so to them it was worth the risk.