My point is that D&D tied combat power to social and knowledge power where these 3 are independent in ASOIAF.I won't dispute that D&D always does combat better than anything else as far as it's own rules go.
But my practical experience with non-combat stuff - spanning 1e/2e/3x/PF1/5e, decades, numerous players/DMs - doesn't lead me to share your conclusion at all.
{shrugs} Perhaps the difference lies in who we've played with.
It's less about the players and more about the mechanics. If you freeform RP the social and lore part, you aren't really playing D&D are you?
No game does. You need players who are good roleplayers and who are invested in the setting to run that sort of campaign properly, because it is based on ideas, innovation, and value judgements, not pluses or advantages.
Which is why the OP's situation is so clear: the GM is offering a campaign of nuance and thinking, and Player X wants to run an Elf. It's a clear situation of a player who is not suited for the type of game proposed.
No, you could design a game based on lore, diplomacy, titles, and domain management.
Like a mix of dating sim mixed with a 4X.
Kinda like playing Crusader Kings with dice.
If fact, the elf player could be one of the most serious one seeing how haughty and twisted a hardcor fey style elf could be. Fits right in.
Sir Sneak is the one doing it wrong. Knights in GOT don't sneak, they fight.