You're telling me that the developers of NW - FSE - who have essentially kept Warband alive and helped significantly to fund Bannerlord and future TaleWorlds projects haven't been given the tools to help them sell MORE copies of Warband and get TW MORE money? It makes financial and practical sense to give a developer the source code if they are keeping your franchise alive and getting you more money. The argument that "The value of the source code overrides this" is completely irrelevant when we all know that Warband may very well be dead without Napoleonic Wars.
*Anyways this is just my opinion- thanks for reading*