Why is Greek mythology and religion generally dismissed but the three main monotheistic texts are often taken seriously?

Because they are popular.

Sheer number of followers? Each of these religions holds great sway over the attitudes of the world through their believers. It’s a politics game, and they have the popular vote, as it were.
When compared to older, possibly polytheistic religions, I can only point out that the civilizations that followed such traditions have often died out or been conquered. While this is not true in all cases (see: Hinduism) it is safe to say that Greek mythology is now considered as “dead” as the language, and if there are any devout followers, they have little to no power to shape public opinion.

Not sure. I consider all religions to be equally valid, which is to say, equally fictitious and equally play no role in my life.

Although, I will say the Greek gods (well, actually ANY other God) are great to use in a religious argument against the existence of all Gods.

“they were accepted at the time when less was known about the world”
This is exactly it. God, in all of its humanly incarnations, is simply a way to explain why things work when they didn’t know, so as to let people not dwell on questions like “why are we here” and “where did we come from” and instead focus on raising a family and being good people.

If someone came up to me and said the storm was caused by any god, I would laugh, because I know that storms are caused by storm systems and weather, not by some god dinking around with our planet.

Everyone knows their religion is really the right one. Just ask them. There aren’t many Ancient Greeks around to assert theirs.
I do find it interesting that most religions, even with their disparate origins and starting dates, have similarly dated holidays and celebrations. The most important holidays align quite well with the solstices.
At the very least, this “coincidence” makes office party scheduling easier.

It all has to do with “clout”, in other words the social and political weight religions carry, and the general rule is that, the more members you have, the more seriously you are taken. Judaism is an interesting exception, since it has a lot more power (even your question more or less equates it with Christianity and Islam) than its population would imply. But that’s not the issue here.

The reason Greek and Roman religions (as well as other such ancient ones) are no longer taken seriously, is that they don’t have any supporters. There are no members to be insulted, to cry out indignantly, to care whether their beliefs are trod upon. Even if Zeus is the One True God, nobody knows that. Yes, there are a couple of thousand Zeists (I don’t remember their exact name, but they do exist), but they are mainly a nationalistic group reviving the old religion out of spite for the Jewish God, and not really believers of Zeus and his Olympian peers. Which is why nobody takes them seriously.

I’m not under the impression that Greek mythology is being dismissed. Many stories can teach us valuable lessons. In Germany a high school (let alone university) graduate would be considered ignorant and uneducated if he or she knows nothing about Greek mythology.

It’s a matter of popularity and history. No one takes Evelyn seriously (not even me) but imagine how weird all those Muslims are gonna feel when they get to Paradise and discover that Allah is a 300 foot tall woman with six boobies. (Allah is simply the word God in Arabic).

I’m sure that John Ashcroft (who is Christian, and not Muslim) will want a law passed to have them covered up. I wonder why he is so scared of titties, anyway?!

@evelyns_pet_zebra ...Or a Borg-like entity with a slightly hooked nose. “Gee, That’s funny, you don’t look Cardassiann.”

funny
i know how to fit dinosaurs and the apes(that we supposedly descended from) in the bible
it’s just a theory though…
anyone cares to hear it?

Because those of the judeo/christian/islamic faiths pillaged, tortured, raped, and outlawed every other belief system out of the places they conquered.

I believe it had something to do with the development of a single deity who is more powerful than all the others, combined. Do you want to get help from a deity that only has one area of expertise, or do you want to get it from the big kahuna in charge of everything?

I don’t remember my history that well, but I recall hearing something about this progression towards a single deity that happened in a number of places at roughly similar times. So I think it’s a kind of human thing—you know, like how all the many different kinds of stores we had in the past are now replaced by big box Walmarts everywhere? A single god has replaced all the little ones, each with their own temple. It’s much more efficient this way.

There’s really only a single God in Hinduism too.
Just many facets and characteristics which are described as unique personalities.

Different times, different customs. Were I a 3rd century BC Greek peasant, I would probably believe in the real-ness of the local deity; and would take care to make all the necessary observances. It still happens today. Farmers do not plant before Corpus Christi (a moveable Catholic feast just before the beginning of the rainy season); when my daughter’s navel string fell off, my husband buried it, with appropriate ceremonies, under a tree in my mother’s yard.

The obscure religions died with their cultures, as Christianity spread under the might of Rome, and Islam spread under the warmonger Mohammed. Both spread by military might, and the cultures they crushed accepted these religions. Eastern religions also prospered through political means, as the more populous groups propagated their religion.
The religions that are currently dominant are also dying, as people realise that religion is not necessary or founded in fact. However, many religious groups are still attempting to hand on to their rituals by inventing hybrid theories that adapt secular elements into their religion to maintain apparent plausibility.
The reason the religions that are currently popular seem to be more plausible is that they have many people working on their behalf trying to maintain the relevance of their religion. Since the ancient religions are no more, thanks to politics and war, there is no one left to explain how modern science is constantly providing more evidence for Zeus or Odin. On the other hand, we have multi-million dollar institutions like the Templeton Foundation that are constantly trying to rectify modern secular discoveries with their outdated mythology.