I kinda disagree with your claim here, but the kernel of truth that I do agree with is that players who hang their entire character concept on their ancestry and class are not creating an interesting character. A character is more than what they can do in combat.
That being said, I think if a player does make a truly creative character, then it's inconsequential what race and class they pick.
I agree completely that it's inconsequential, one issue with the arguement about creative characters is that people often blend being unique with being compelling. A compelling character is where it's inconsequential what choices you make.
That said, I think players who aren't aware of the tropes PC's often fall into may end up playing "the straight man" to the group, who is comparatively very plain. Players who have played for longer may feel that this is similar to PCs they've seen before. But even then, it doesn't really matter as this PC trope shines in contrast to the rest of the party and that rarely changes.
Unrelated but I wanna say how proud I was of my Baldurs Gate3 character. I felt that your TAV in that game was quite plain and generic no matter what you chose, so played as a human fighter called John Baldurgate who was the most generic character possible and had a blast.
John Baldursgate sounds like a brilliant concept for a BG3 PC. Honestly I love BG3 but by far my biggest gripe with it is how boring the player character is. They even built in a solution for this problem with DUrge, but that only enables you to play an edgelord. And if you play any of the main characters yourself, you miss out on their voice acting and character development.
If your character concept is "complete" before choosing your class, consider being a human. Other choices carry along more "baggage" that may distract from what you're shooting for.
Other players can be like "What kind of elf would...?" etc., but they don't do that for humans.
"His name is Hugh M. N. Fi-Tor"
Does the "M. N." stand for "Middle Name?"
Mmh. No.