Companies in general undergo various changes over time. Konami as a company has been around since 1969. You don't sell an IP because you 'want' to but because you have to. Selling an IP is pretty much a last ditch 'We're about to go bankrupt and we need to sell assets to keep the lights on.' maneuver.
Selling an IP is a MASSIVE deal because once it's sold, it's gone and typically pretty much impossible to get back (Because the person you sold it to likely won't sell it back since they bought it for a reason, they'll probably ask a price enormously higher than what you sold it for, etc.)
They won't sell it and IMHO they shouldn't sell it.
