I think
@Yaarel is interested in the sorts of ways that you can "dial up" aspects of humanity.
Elves express a certain conception of human perfection - in respect of ethereal beauty, charm and presence more generally, and the ability to change the world through magic. Some variants - eg certain interpretations of Wood Elves - reduce the supernaturalness and instead emphasis the connection to nature. In some other variants, the otherworldliness ceases to be an expression of perfection and instead becomes a flaw (and Moorcock's Melniboneans and Star Treks' Vulcans can be seen as closely related tropes in nearby fictional works).
But in the D&D game this Elvish-ness is expressed through things that humans can't do - depending exactly on edition this might be low-light or infravision, automatic magic or "fey step", preternatural resistance to magical enchantments, etc.
Dwarves express a certain conception of human greed and technology or manufacturing-oriented striving: they are miners, they love golds and gems, they are very clannish with traditions passed down through generations (like an artisan's family or guild), they have a certain hostility or at least stand-offishness towards outsiders. Much more often than is the case with Elves, a lot of this is presented as flawed rather than perfect.
In the D&D game this Dwarvish-ness is expressed through things that humans can't do - depending exactly on edition this might be infravision or darkvision, magic and/or poison resistance that reflects both their physical stamina (as workers) and also their disconnection from certain aspects of nature and the supernatural, and preternatural abilities underground (eg detecting distances, observing stonework, etc).
Halflings express a certain conception of simple human pleasures and relationships - self-respect without too much pride; a love of creature comforts but an ability to go without when duty and circumstance demand it (just like war-time rationing!); a general distaste for "action" or violent self-expression, but a willingness to "muck in" and get the job done if that's how it has to be.
At least as I understand it, Yaarel's objection is that In the D&D game this Hobbitish-ness is expressed through things that humans
can do and be: being little, being brave, being a little bit lucky. I'm not sure that objection is quite as strong as seems to be asserted - eg I think 5e Halflings still have remnants of the AD&D feature that allows preternatural stealth, beyond what one might just expect from being small - but I can still feel its force. The mode of humanity that they express is not really captured in a distinctiveness
in the fiction and the accompanying mechanics, but rather by simply doubling down, in the fiction, on the fact that they are bucolic, comfort-loving stay-at-homes who occasionally spawn plucky heroes.
(I will also add that I think pointing to their strength-mass ratio doesn't really help here. The fact that Halflings have workable strength is purely a trope to (i) make JRRT's fiction work and then (ii) make the D&D game work. It's not any sort of commentary on human biology or divergent evolution.)