Just because they've done 4 setting books recently doesn't mean they are likely to go back and do a new Realms setting book (especially one that covers all the parts that aren't the Sword Coast.) Three of those setting books are completely new lands, so it is information that players never had before. And the other one is basically a rehash of the same two books they had just done for it in 4E and 3.5.
I sincerely believe that the current brand officers of D&D right now do not want to rewrite or "update" information for past settings they have already done before, unless it is a part of a specific area that is bounded by an adventure path. So we'll see a little touch of Greyhawk around a Saltmarsh book, we'll probably get a bunch of Planescape stuff when the autumn's planehopping AP is released. And of course we got a bunch of updated Realms info for areas where their APs occurred.
But I still think anyone who is expecting a stand-alone Forgotten Realms Campaign Setting book (ala 3E's) for the entirety of Faerun is going to be left disappointed, because it is nothing more than "updated canon". And WotC still does not want to spend their time just updating canon without having some other reason (like an AP) to do so.
I sincerely believe that the current brand officers of D&D right now do not want to rewrite or "update" information for past settings they have already done before, unless it is a part of a specific area that is bounded by an adventure path. So we'll see a little touch of Greyhawk around a Saltmarsh book, we'll probably get a bunch of Planescape stuff when the autumn's planehopping AP is released. And of course we got a bunch of updated Realms info for areas where their APs occurred.
But I still think anyone who is expecting a stand-alone Forgotten Realms Campaign Setting book (ala 3E's) for the entirety of Faerun is going to be left disappointed, because it is nothing more than "updated canon". And WotC still does not want to spend their time just updating canon without having some other reason (like an AP) to do so.