The argument that religion is a necessary part of society is pretty lacking my view (not that I think anyone has made it specifically yet). I don't think faith is what's important as much as belief (though I suppose they are sort of one in the same). Belief can take a number of forms, be a guiding principle of a person's life, and avoid religious connotations. It's possible to be guided by a philosophy which includes moral concepts and be a productive member of society who has no need for religious beliefs. As such, I don't see why supplanting religion with a particular philosophical bent wouldn't work for an entire society the same as it does for an individual.
The religious like point at failed states that were Atheistic as a counterexample to this, but they fail to take into account several errors in their judgment:
1) There have been very few Atheistic states. Certainly not enough to form any sort of reliable sample for judgment.
2) All of the examples of Atheistic states that are true examples also happen to be Communist states; there are two correlations here, and they're not controlling for that as a potential cause for failure (as opposed to the purely secular component).
3) They often give examples of states that were in fact not at all Atheistic while making their arguments, such as Nazi Germany. Nazi Germany was not an Atheistic state.
4) There has never been, to my knowledge, an Atheistic society to actually judge. In Modern Western Society we don't really have religious states, we have nations that happen to have religious cultures, but the government takes no position. If a state enforces Atheism as part of its government, that is essentially a Theocratic arrangement. Judging Theocratic arrangements as a "proper example" of a secular society is obviously going to skew the data if liberty leads to stability (which most would agree it does).
To be able to actually judge fairly you'd have to find an example of a largely secular society that has conditions, rules, and a constitution similar to other Western Societies. Clearly the data is lacking. I suppose it could go either way, maybe it's true that society can't exist without religion, but until I actually seem evidence either way I'm choosing to believe in the potential of secularism (see what I did there?).
EDIT: As for what studying cosmology and the origins of the universe is good for, well, you need a very solid model before you can make predictions about the phenomenon that is being modeled. If we come to understand how the big bang happened precisely then we can work forward through time from there and understand the formulation of literally the entire universe. A greater understanding of that will allow us to better predict the behavior of our own solar system, to understand the likelihood of finding other earth-like planets, and it will also lead to a greater understanding of the underlying patterns in our universe.
While we work on grasping that problem, we also refine other laws and concepts. Attempting to understand the Big Bang has highlighted potential errors in other fields of science. String Theory certainly wouldn't exist without some of those concepts, and string theory has the potential to greatly unify our understanding of reality.
When we actually travel in space, and we will have to some day if we want to survive the death of our solar system, all of this information will be of immense importance for us to understand. Right now, it's true that there isn't a whole lot of practical use, but in the future it will be very important.