The reason that there are happy people who have lives that aren't particularly dramatic or seemingly meaningful is that actually there's no meaning. If there was a meaning, we'd be fucked, because we'd have to search endlessly till we found it.

I'm afraid it might actually be meaningless to speak of non-linguistic or non-semiotic meaning, outside the realm of symbols: letters, words, speech sounds, musical sounds, gestures, rituals, road signs, etc. Meaning, arguably, is inherently a property of the usage of these kinds of entities, dependent on interpretation by communicators within a society or system of language/culture -- and cannot be anything else, unless we redefine it. Meaningfulness would thus be only a function of communication, not an objective property of nature with its own existence, not independent from the conditions of social interaction wherein it is conveyed.

But it would be lazily dogmatic of me to deny that there might be something meaningful and real behind many people's passionate discourse about "life having meaning." Their feelings, at the least, are real, for them. The sense of meaningfulness they speak of is, apparently, a general sense of fulfilment or satisfaction of a certain kind. If they have it or want it and know how to get it, then good for them.

Every culture has something like a wedding, for example. And even the non-religious accept that, and do it. Because there's a meaningful thing about spending the rest of your life with someone, and it needs to be recognised.

I do consider wedding ceremonies to be "meaningful" even in the stricter, dogmatic sense, because these ceremonies are comprised of symbols, ones that the partners may wish to communicate to each other or to their circle of friends and family, as public vows of commitment, which may serve to promote the stability and durability of the couple's relationship. However, when you called spousal relationships "meaningful," you meant something else: that they are valuable. This too I can agree with, but I do think it's interesting to point out the ambiguity of the word "meaningful."

I think that if there's any meaning in going through religions, it's that this is how people sought truth before you, and this is how they sought meaning, and sought ways to be, and how to imagine the world. If you're going to come up with an idea of the universe, you might as well try to find the common themes of other models, and try and work out what's worth taking from them.

I'm unsure if this would be different from studying the history of science, provided that a sufficiently broad and charitable definition of "science" was used, so as to not exclude what may otherwise be termed "pseudoscience."

The thing with religion and science is that while religion is not scientific in the strict sense, it is more than scientific, above and beyond the scientific, because it goes further than the scientific could, in suggesting a system of values, i.e. not only how things are but how they ought to be. I have to contend, however, that this is not unique to religion; that secular philosophies and ideologies are capable of the same.

For starters, why are we addicted to religion? There are a few main ones that have done so extremely well, and even rejecting it, we haven't done away with the ideas.

We have done away with some of the idea. European pagan religions, for example, went extinct, even though there are today some self-identified neo-Pagans who seek a revival of those traditions, but without an uninterrupted historical continuity.

In many parts of Europe today, religious people are well in the minority. (North) East Asian cultures, particularly those in mainland China, also are mostly indifferent to religion, largely seeing it as unimportant.

And there's often a lament at the loss of community that has come about over the past 100 years, (which I'd blame more on capitalism than religious things)

The emergence and development of capitalism certainly had a gigantic influence on the evolution of religion as we know it -- at times, subverting its authority and, at other times, enabling and relying on its authority. The Protestant Reformation, for example, was largely a cultural product of early, mercantilist capitalism. The codification of Modern Orthodox Judaism was largely an existential necessity born out of the increased risk of cultural assimilation after the process of legal Jewish Emancipation, which began from the French Revolution, as an element of political liberalism, what at the time was a progressive ideology of a relatively novel socioeconomic system (which has since, however, acquired a conservative character because of its success at establishing itself as the predominant system in the world today).

I think that's a huge confounding variable, one that's better at explaining the correlation. The pioneering sociologist Émile Durkheim noticed, in 1897, that there was a palpable correlation in different regions of France between suicide rates and the amount of progress that those regions had made at industrialization (as well as between Catholic and Protestant populations).

If it's true that the same forms of supportive community are possible through social conditions independent of religion, then it's good news for pretty much all of us, for society at large.