>>3808657 (OP)NWN was the realization of the vision of one man, Trent Oster. He imagined a game that was like a boxed set of D&D and everything that entailed, from creating your own adventures, to playing together with friends, and a DM guiding the game. Without someone like Trent Oster you will never get another true NWN successor, it will always be a GM client tacked on, or modding tools tacked on. This is because the people making those other games don't have that same vision. Their vision is making money while telling a pre-made story.
Trent Oster hoped to get the funding and license to make BG3, but that fell through, and instead it went to Larian, and now you get gay bear sex.
Without proper funding, Trent Oster can never direct the production of a new game like NWN, and in the end it is all about the money. Plus the price tage to produce a new NWN-style game would be much higher and more risky than a regular style RPG, it would have to be a true passion project. That's why it is unlikely to ever get a true spiritual successor.