From the business perspective of wizards of the coast, i don't see RTWP making much sense. They would please some fans of the old games if going for RTWP, but that isn't to profitable compared to capitalizing on the surge of new people in the hobby that has been exposed to DnD from the likes of Critical Role. Since turn based would be a lot more faitful to the actual 5e roleplaying game then RTWP, I think advertising to players that you can experience 5e by playing Baldurs Gate 3 is a much better idea then going for RTWP to please some of the old fans. It would work the other way as well, people that has not played the pen and paper game, might get more intrested in doing so after playing Baldurs Gate 3, if its turn based.
Also, why would Wizards say that Larian is the perfect studio for the job, if they are not planning for turn based, when Larian is known for turn based.
Why not both? Some have asked. Well its a lot more work ofc. But if you look at the tacked on Turn based from Pillars 2, that dosent go over to well. Some of the combat mechanics like incresed attack speed dosent work in turn based, it just make you go first in a turn, wich isn't that huge. The engame bosses are extremly slow fights because they are made for a system where attacks happen much more rapidly. When doing turn based you need to design the game for it, removing useless trash fights, and instead have mostly intresting, harder fights. And having to powerful healing so fights go on forever isn't a good idea.
So I don't think we'll see both systems either.
I agree, there are a lot more D&D fans now then BG 1&2 fans and even more so if one excludes BG fans that willing to except TB.