So much agree here, but one very important disagree:
Maximising wellbeing is the goal of humanity, and all activities should be in service to this underlying tenet.
There is no sophisticated goal of humanity. Even "Human Rights" are a derivative of a culturally dominant part of humanity, but they do not represent all of humanity. Our cultures are so incredibly different, and instead of seeing that as a strength, we try to put it all under one wing.
(The only goal of all humanity is that of all species - spread genes.)
Well-being means totally different things to different cultures. Some are better living for the next life. Some are better living according to the rules of some god. Some are better thinking for themselves. None of them is a better or worse human per se. They just have different perspectives. But then, as mentioned in other posts - what if there are universal laws and rights?
The commercialisation of everything leveraged our purpose of survival and used it to productise goods and services that would create ambiguity and uncertainty in what the right path is.
That is the key. Making money is easier if the marketing target is plane, as in superficial. The less real diversity, the easier it is to convince them of buying, keeping the machine alive. Cultural diversity, with all its inherent conflicts, does not make a good market. It makes a reduced market, a niche market except for basic (really basic, like potatoes, not flavored toilet paper) necessities which it can usually cover itself.
There is a vibrating connection between the system we comfortably live in, that we're being well in, and the direction that the cultures we know of are going. It does not come out of thin air.
As a species yes, but is that all "humanity" is? If it were, we would have evolved to create food and fuck. At this stage, we have the food, but the fucking is decreasing rapidly.
In detail yes, but at the core? I don't think so. The idealistic view might suggest it, but the practical view of individuals are unlikely to back that up.
And what we have done globally is condition homogenisation of thought and habit. The global cultural overlap is growing, as we all start to resemble the marketing plan.
As a whole? Yes, we're primarily bodies, animals. That's what we all have in common, all together. And that's where it stops. Everything that comes after, all the values and such, are splintered among the cultures as we all weigh them differently. I just don't think it's enough to be able to conclude that "Humanity as a whole strives for well-being." Yet. As you write, cultures are overlapping more and more, which is a shame. There are positives to it, but in my ideal world, we would have many cultures that get along with each other. But that's an utopia.