Last night I came to wonder if perhaps the success of the Sailor Moon franchise should be credited more to the 90's anime than to the manga proper. 

While the manga indeed provided the source material, it didn't quite provide the development of the characters themselves. What we were in turn left with is precisely what Crystal presents us with now. So I have to wonder, perhaps we read the manga and watch Crystal (amongst other adaptations) with Sailor Moon Classic in mind, and not vice versa.

Would anyone much care for the series and characters were it not for Classic?

There's a bit of academic chat on Sailor Moon revolving around feminism and the like. They're kind of like female Power Rangers and they were part of the "girl power" thing going on in the 90s (Spice Girls and the like). They were breaking the traditional helpless female role. I think that's a pretty solid reason as to why Sailor Moon is so popular. It's like the mother of magical girls.

As for the anime - as great as books, manga, and comics are, we like to see things moving. That's why books become movies and such. It became it's own universe, taking a Power Ranger route with monster of the week, and it thus entertained kids. The formula of the previous series was a good one, IMO.

I'm sure Crystal has brought in new Sailor Moon fans that started with Crystal and worked their way backward. It happens in "reboots", especially when it's a reboot of something old. I'm sure it's rare for a modern, 20 something Doctor Who fan to venture back to the reeeeeeally old Doctor Who episodes (are they even able?). I could be wrong on that, but yeah. I'm sure the same thing is happening here. Just us fans from the olden days are also mixed in.

I can't say the popularity came from one version because so many people have different versions they like. Many aren't a fan of the classic anime as many aren't fans of the manga. Some like the live action more, some loke the musicals more.

I think Sailor Moon is not as popular now simply do the fast and chaotically planned new anime.

Back in the day, Sailor Moon was a handful of Magical Girl series unique to its kind. They were all different enough that they didn't feel like copies or ripoffs.

Today, MANY MANY MANY manga and anime throughout the years have mimicked or drew inspiration from Sailor Moon and gave it so many twists and etc. ...that it's just not so magical anymore in comparison to the hundreds out there like it.

That's my take on it anyway.

Well to me, as much as I like the comic/manga series there really wasn't much of an engaging story. We see those problems within Crystal. It's very difficult to communicate much about the characters in the way that it was written. It's only, because of Classic that we see that source material developed as th characters we know and love. Sailor Moon wasn't a long enough series manga wise to allow for much in the way of character development. Of course, one can be a manga purist (I'm something of the sort.), but even I have to admit that the characters from Classic allow me to better enjoy the manga, in spite me preferring Crystal sticking to the source material better.

There would be no Usagi, Ami etc. as we know and love them without Classic.

I don't agree that there is no Usagi as "we know and love them" sans Classic. I haven't seen all of Classic. The only season I have seen fully is S when it was first it aired. I was probably 10. For reference, I'm 27. I don't remember the first season, and I recently bought R, so I'm watching some of those episodes for the first time. Other then that, I had the manga, which I read so many times from 10 to... well, now. I spent way more time with the manga than the anime growing up, so the personalities from the manga are what always stuck with me. Usagi has always been a lovable goofball in the manga, and it showed this wonderful maturity throughout as she grew. 

The manga was an easier touchstone for me than the anime because I was able to pick it up and read it whenever I wanted. I didn't have the same ability with the anime. 

I do agree with you though, that there is a lack of development at times, both in story and characters in the manga. But the overall themes of love of all kinds, friendship, and kindness all resound in the manga. 

I guess, to answer your first question, I adore the series. And I adore the characters and the story presented in the manga because they were my main version of enjoying the series because of a lack of access to Classic growing up.

See I do remember the anime and that's what brought me back into SM, I was at a Con and I had attended a magical girl panel and we started to talk about it and I was like OH YAH I use to watch this as a kid, so I started to watch it again and well, the rest is history. 

I honestly think it just depends where you are in the world and how old you were will really dictate what brought you into Sailor Moon and thus the success. Manga at the time the anime first aired were very popular in Japan but no so much outside Japan. Anime is what really started to make Manga popular outside of Japan, people wanted to find out more.

I love all adaptations of the story, but the Sailor Moon manga captured my initial attention much more than the anime. I saw the anime first, and I loved it. It's a very different experience to read the manga versus watching the anime. I always enjoyed reading, and imagining myself alongside some main character's exploits.

Reading the manga emotionally connected me to Usagi as a character. The manga has a focus on Usagi rather than anyone else; that didn't bother me as a written and illustrated work. There were moments in the anime that I didn't care for Usagi—too loud, whiny, etc. In the manga I found more of her vulnerability and how it feels growing up. Of course, I was reading it while I was slightly younger than Usagi and then continued reading it as I reached her age, so part of the connection could have been related to how much I wanted to be her.

Even without the original anime, I would have still embraced the series because of the manga.

I think what makes Sailor Moon Sailor Moon is gonna be different for many people. In some areas the manga was available before the 90's anime (this was the case in China when I was growing up, where "knock off" copies of the Sailor Moon manga were cheap and accessible to secondary school age children) so for many readers this was the first version of Sailor Moon they encountered, and it forms the core of what Sailor Moon means.

I know I was never bothered by the lack of development for the villains in the manga as a child; that was something I only became aware of as I got older. However that never diminished my love for the manga. I guess it's kinda like a food item you grew up with: what stuck with you as a child will likely continue to stick with you for the rest of your life as the "definitive" version even if other versions come along later I have no idea if this analogy makes sense, but for some reason I have a tendency to make food-related analogies. OTL

Even though i prefer the manga over the anime dont get me wrong i love every adaption equally, but
i feel as the anime has more to do with making sailor moon sailor moon. I feel like alot more people enjoy it over the manga as the anime was alot more "fun" you know you had that jazzy music and those great transformations ! and with the manga it was a bit more serious and i feel like it is something you would have to read a few times to get it in whole (at least i had to haha )

but to me personally i do prefer the manga and i feel like it shaped it for me, i feel like usagi's character is better portrayed and i feel as if the series is more mysterious.. and i just love naoko's art its so beautiful!