I see zero reasons to use DND in an action game. The world of Faerun a collection of bad fantasy tropes with a few good ideas. The only thing that makes it interesting are the mechanics. Maybe Eberon but no one really likes Steampunk...
I highly doubt that there is demand for such a game when there are better fantasy IPs with more unique ideas.
Well sure. That is certainly a point open for debate. I strongly disagree, but that's just one person's personal view versus another's. But what matters here is what WotC sees. Are they going to agree with your view of D&D and the Forgotten Realms? Hardly. And keep in mind that a major part of the changes of D&D 5e was to change the default setting for D&D from Grayhawk to FR, so for WotC part of the success story of D&D 5e is FR's popularity. So why wouldn't WotC want to make a D&D ARPG? They have been licensing D&D for a very wide range of different types of games in recent years, and most of those games have sold at least ok.
On a more personal level, I do find it interesting that we are diametrically different in our preferences. For me, it is precisely the Forgotten Realms setting that I love and which I find very interesting (and as such obviously also don't agree it's a "collection of bad fantasy tropes"), whereas I significantly dislike D&D rules and mechanics.
