I actually don't want FR to emphasize Dragonborn for those reasons.
What I want is for people to stop saying Forgotten Realms is a 5.5e style setting because it doesn't embrace the style of 5.5e. it allows Dragonborn and Goliaths as playable species but it doesn't truly embrace the idea. It just now started giving Gnomes and Halflings love. But Forgotten Realms is really a human, elf, orc, and dwarf setting.
I agree with your characterization, in that the Sword Coast regional setting makes the common species be Human, Elf, and Orc. But it is an evolving kitchen sink setting that adapts to each edition, sometimes in "realms shattering" ways.
In 2e Forgotten Realms, the Human and Elf were the popular species. The Orc species was the go-to adversary for almost every low tier adventure. The Dwarf was less common in 2e too, but always normal with readily accessible lore for any player group.
The Halflings were treated as if little more than a small human ethnicity, who were wherever other Humans were. Gnomes were like a dwarven ethnicity who could do arcane magic, who were wherever Dwarves were. The Forgotten Realms setting entered D&D with these all of these popular old school species and assumptions in mind.
But the Realms continues to evolve. Even now, emphasizing how Halfling and Gnome are actually "species", is forcing designers to think more clearly about where these species came from, and how they got to where they are now. As you say, only now are they getting setting lore love. The Forgotten Realms is evolving.
The same 5e 2024 attention to detail that encourages spelling out the Halfling and Gnome, might also encourage hesitation for how to do this for Dragonborn and Goliath, exactly.
Still, I expect Dragonborn and Goliath to find a way. Consider the Drow lineage who went from playable monster to a fully normal Elf lineage. The only reason for this was popularity. For sensibility reasons, the Orc went from monster to normal. So the setting is now in the process of better integrating them into the local cultures.
Forgotten Realms evolves according to the edition, but it is a process.
I see a flaw in your logic.
There is a difference between "heres how to explain this weird option" (Dragonborn), versus "here is how the Dragonborn are a significant part of Sword Coast".
Currently, the Dragonborn is still weird. I expect future Forgotten Realms product for come up with a satisfying amount of love for Dragonborn. Because. This is a popular species, and many Forgotten Realms players play Dragonborn. There is a demand for lore ... that also works seamlessly.