So for example: they'd have to make you a Noble of a specific family to be able to create a compelling story/dialogue around it.
Not necessarily, it could be as simple as including lines like "[NOBLE][INTIMIDATION] Do you know who I am?" where appropriate with a success resulting in the other party being flustered and submissive while not acknowledging any specific background lore.
Similarly, for Folk Hero, the Player's Handbook has a "Defining Event" table, with Descent into Avernus having a variant Baldur's Gate specific table. They could quite easily have you pick a defining event at character creation and have dialogue options appear when relevant. Obviously this is far more work than ignoring background, but it would make the choice of background feel more important than it currently is.
Though I suppose they could make it... vestigial/low-key but present? It would still be nice. Like being able to make a pompous answer as a Noble, express being uneasy in a city as an Outlander or mention familiarity with hard life on the streets as an Urchin. Small, generic stuff, but still a bit of background acknowledgement.
Exactly this. Race and Class are acknowledged by granting extra conversation options when relevant, so why shouldn't background? If they are not going to acknowledge it in gameplay, then the background section of character creation might as well be a free choice of any two skill proficiencies.
