Originally Posted by
Sutekh
They haven't even come close to scraping the bottom of the barrel for properties they already own and can put on-screen, so it doesn't make sense for Disney to just throw money away buying the rights for the sake of completeness. Maybe fifteen years down the road, after we've already had Thunderbolts movies and Young Avengers movies and Champions movies (or, shudder, they've done their third Iron Man/Thor/Captain America/Avengers recast/reboot...), there might be a desire to get Namor back 'in-house,' but at the moment, there's no reason at all to spend that money.
It's also possible that if they wait long enough, they can get the rights back for cheap. It's not like they are starved for IP to use until that happens and desperate to spend money they don't need to.