On society: simply a matter of personal values -- and subjective to its core -- especially in the case of defining "best." The only other "branch of thought" that shoots out is that the current U.S. society is the most enmeshed within the lives of its people. Again, whether or not this is a "good" thing, something to be lauded or decried, is individual.
In the past, you were not a "part" of society; you simply co-existed. Your main "society" was local, and its influence and demands did not have the same reach for the commoner until mass-communication took off, and became readily (and cheaply) available.
To some this is regressive towards individualism. To others this is a glorious advent towards improving material circumstances.
On the last, while material circumstances have improved, those of the spiritual (non-religious) nature have dwindled. There is ever less room to be human, "boxed-out" by the burgeoning, frenetic, and all-encompassing need to be a useful part in the whole.
Materially, the person working 2 jobs is better off than a literal serf; but in the incorporeal, both are still slaves in soul -- needing to labor for another in order to survive (while the other can simply live idle, and survive by virtue of his slaves).
Another branch could be that the serf didn't know he was a serf. He was not educated, nor cognizant of much but the (few) people around him. His spirit was simple, and wanted of little but base primal needs. Were he to learn he was as serf, I'm sure his spirit would become broken, knowing full well how terrible his circumstances are (in relation to his betters) -- and its crushing inescapability. But without such, he simply lives his life, as that's all he's known. There is no ephemeral "greener pasture" to keep on striving for until he drops dead (spiritually, and physically). He knows not of anguish. Discomfort and physical abuse? Yes. But of spiritual anguish he knows not.
This can go on and on in many different directions, but suffice to say I see it as moot.
On noblesse oblige: main proponent of change? I believe never. Its simply theatre; a social nicety. All it does is "smooth" any "ruffled feathers," and helps hide the disparity in material circumstance; as well as soothe negative emotions -- stopping them from cascading into general class-antagonism, and slave uprisings.
The increased visibility of the vast swathes of nouveau elite means their actions are under constant scrutiny by their lessers. Instead of reveling in degeneracy and exuberant opulence "behind closed doors" as the old elites did, they now broadcast it to the billions of proles, inadvertently reminding them that there is a "greener pasture." And as our hypothetical serf, all-aware that it is an utterly unreachable height (that is, if one hasn't been completely deluded by one's society or oneself into believing it is possible).
The simplest rule of governing over the masses is to make them believe their lives are good and well -- that they have everything they could ever want; that there is no "greener pasture." That the encroachment onto the soul of the common man by society is for the benefit of the common man, and not simply a way for the uppermost crust to simply subsist on their labor. Perhaps even that there is no encroachment onto the soul at all, it simply is "all they've known," and "how life is."
In this respect, a lack of noblesse oblige is just one example of the failings of our betters in managing societal progression, in-spite of the boorish and ever-deepening entanglement of "society" within the life and spirit of the commoner.