The previous remakes of BG1 and Icewind Dale ( and as yet unfinished SoA/ToB ) were made for the NWN2 engine, which, like the NWN1 engine were explicitely designed to allow a community of modders and persistent world maintainers to create ( or in this case recreate ) their own stories and worlds.
There are thousands of game experiences made using these engines by creative individuals and groups, aimed largely at other creative people, along with those players who are prepared to enjoy non-professional, spare-time developed games, without being hyper-critical. These game engines are now 20 years old, so they are not that much newer than the original BG games. But they are also from a time before the widespread use of motion/performance capture, use much simpler assets ( fewer polygons, no layered models ), and are 32-bit programs which imposed limits to how sprawling you could make your stories.
The BG3 engine is not ( as far as I am aware ) designed with amateur game development in mind. There have never been any specific promises about how suitable BG3 tools will be to create a totally new story, or if this will even be supported. Without official tools, a great deal of BG3 added and changed content has still been possible, but the main thing that sets BG3 apart for many is the performance-captured dialog and cut-scenes, which are beyond the capacity of small amateur teams. Coupled with the need to create the many unique 3D assets that enable the previous stories in BG1/2, and the probability that some needed features cannot be added to the engine, I doubt that anyone is likely to try.
But if someone did succeed in remaking BG1/2 in the BG3 engine, and I am still alive ( BG1 took 7 years to remake in the NWN2 engine, in the BG3 engine it would probably be longer), then I would probably play them, if for no other reason than to acknowledge to effort put in.
