I rather liked it. Valerian and Lauraline were both likable, and the plot was engaging. It was pretty obvious Clive Owen was evil once he tortured that guy

There's a Boss Nass film coming out?! Awesome! I'm there.

#sostoked

I'll be a bit more kind to both movie and general audience: there are a lot of good movies out right now, so competion is fierce for people who only go to see 1 or 2 movies a month, so Valerian has to attract more attention than say... Dunkirk, which has a famous director or Spider-Man, which has name-recognition. Movie success and movie quality are only tenuously connected (Hello, Transformers franchise), so in a busy movie season like this you'd need something to draw attention, whether it is a director, actor, visuals, source material or something else.

(Example: for me I had time for 2 movies in the cinema last month: going to the cinema takes a certain time investment that just putting on Netflix or so, doesn't. So I picked Valerian, because I love the source material and I picked Baby Driver because I love the director. I'm sure there were more great movies out there that month, but I didn't have the time to see them.)

So what's there in the trailers for the vast audience unfamiliar with Valerian: not much, really. You are dismissive of point C. that the trailer was not very clear, but the trailers were just not very good for this movie. The trailers don't do any great job of selling us on the world or the relationship between the two main characters (not going into how that relationship was just so much better in the comics compared to the walking HR disaster that movie Valerian is). We get brightly coloured sci-fi environments and CGI monsters, which may draw in some, but it has been done before, quite often, so it's not a unique draw for most of the audience and we get nothing else from the trailer. A bit more of the way Valerian and Laureline work together (more attention to Laureline in general for that matter) to sell our heroes to the audience.

So, we lose a lot of audience already at that point. The bit more interested potential audience member will then look into the movie a bit more: why should he or she spend money on this? We get no plotline from the trailers, just unconnected action scenes. The actors are relatively newcomers or not big names (having Rihanna as one of the big names doesn't do it any favours either). It has Luc Besson, but the Fifth Element's reception was already mixed (and that one did have a major action star in its cast) and Leon was a long time ago and a very different movie. Since then Besson hasn't made any big successes really; Lucy was mostly coasting on Scarlet Johansen's popularity.

So those youtube videos you saw were not exactly wrong, but they were not completely right either:
None of the points you mention are indeed the big reason why a movie has success or not, but each of those movies had other things going for it:
- Guardians didn't have recognisable source material, but it had the Marvel logo that came from a string of successes, well-cut trailers that set up the premises of the movie (rag-tag band of misfits save the galaxy) and raised interest (use of older, but recnogisable music, some good jokes). Its actors were not A-list, but still relatively well known.
- Pirates was a gamble, but it had relatively little competition when it came out and we were not sick of Johnny Depp yet at that point. Also it had a great cast and visuals. Again trailers set up the story well.
- History of Violence: The odd duck in your list of movies. It was a critical success and it definitely made its money back, but it's smaller, more quiet movie. Drawing on the fame of its director and its major actors (it has to, because it has no amazing visuals or hook to draw on, the actors do all the heavy lifting).
- Avatar: it had the 3D gimmick, which was new (well, new again) at that point and it had James Cameron, director of several of the greatest hits of all time. Like Valerian, its trailers were colourful and filled with weird aliens, but it was never the hook for that movie.
- Star Wars: Star Wars success was a bit of a suprise at the time. It was a time when movies and marketing worked differently from today, Valerian is one of many sci-fi action movies released this exact summer, while Star Wars was pretty much unique at the time.

Your conclusion that we therefore will only get prequels, sequels or reboots is a leap: just look at the success of The Martian or Arrival (keeping it to just sci-fi movies). Valerian underperformed for a variety of reasons; it was not a bad movie, it probably deserved better, but I also had problems with the movie, so if a critic didn't like it, I can quite understand that.

Hi ! Very interesting to read you all. I was a huge fan of "Valerian" in the 70s, when I discovered it (in French). I still own some issues. "Valerian" was very new for this period, with two characters having weaknesses and making mistakes (sometimes) - and also, from a visual point of view, it was a very new way to draw E.T. worlds. Later, I have been lucky enough to meet Jean-Pierre Christin, and he is a great guy, with many original ideas, and a never ending imagination. But I have to say that I have been a little bit deceived by the movie : it too far from the comics atmosphere, and a little bit slow, with not enough spectacular scenes. It's fun, but not fantastic.

Finally, saw this film on SyFy the other night (not sure of actual run time of the film but they stretched it out to 3 hours with commercials. UGH)

Must say, enjoyed it very much. The visuals were simply stunning (wow, to have seen that on the big screen...) and the plot was rather straight-forward. The European sci-fi aesthetic (as with Fifth Element) was a fresh change of pace. My only quibble would be the romantic angle between Valerian and Laureline; it felt forced to some degree, like that should've been a character element introduced in a possible second or third film of this franchise instead.

I haven't read any of these comic volumes yet but checking on Comixology, they have the first five, six volumes available for free to download via Unlimited. Now, I can catch up on it since I'm intrigued to learn more about this series after this film.

It's definitely worth watching. The things I disliked - mostly the way Valerian was written, cast, and performed and the romantic relationship between that character and Laureline - do take up far too much of the movie, so they can't really be ignored, but there are more than enough positives to make it both fun and interesting for any SF film fan, or even any film fan period, if only for the visuals.

If anyone is looking to buy the originals (in French) second-hand from eBay or wherever, try to avoid the 16/22 editions from Dargaud. They're a smaller format (160mm x 220mm) and the art has been cut up and rearranged so that one page of the original takes up two or three in the reprint. Sometimes panels are rotated, cropped, or flipped to make them fit.

That's why they're cheaper.