I think that some material is better for adaption than others, irregardless of it's original medium. The problem is that the guys doing the adapting rarely care about the suitability of the material, so much as whether the franchise name is going to get attention and draw people in.
Some people are probably going to want to lynch me for this, but I thought that first Mortal Kombat movie was actually pretty decent. It could stand up fairly well if you didn't know if was a video game, and I've seen far worse movies in the martial arts genere. It worked as well as it did, was because the plot of the game was pretty simple, basically a Gladiatorial fight to determine the fate of the world conducting on the island of an evil sorceror. It was basically "Enter the Dragon" with more camp and supernatural stuff thrown, the bad guy being a wizard as opposed to some dude who likes to screw weapons onto his arm stump, and the wizard is out to pretty much unleash hell on earth, as opposed to just running a heroin syndicate. Now granted the costumes and such could have been better, but a lot of the choreography was decent, and it got the job done, and while it didn't really go heavily into Mortal Kombat mythology and altered some of the characters, it got the job done.
The sequel to Mortal Kombat was however horrendous, but largelty because they decided to make it more complicated, and managed to cross that line from camp to just absolutly ridiculous.
It's basically the same as the short stories, as opposed to novels. Except with games you really need one that hits the sweet spot of being basic, while still having an identifiable amount of lore that gives it a unique and identifiable feel. If there is too much or too little there it's going to fail.
I see the failing mostly be on the part of the guys making the movies picking the wrong games to try and turn into franchises that exist on multiple platforms, rather than video games inherantly being unsuitable to make games out of on general principle.
It's the corperate mentality in action, when a video game movie gets made the guys doing it probably look at how popular a given video game franchise is, and then decide to adapt it, relying on name recognition to sell tickets irregardless of quality. I very much doubt you see guys looking at video games, finding one that looks like it could be turned into a good movie, and saying "hey this game isn't really popular, but we could do a good movie out of this and make some money". Largely because the latter doesn't hold the promise of guaranteeing huge piles of money for minimal effort. If you saw differant standards used for finding games to make movies out of, and slowly worked on doing this kind of thing right, I think there would be less concerns over potential adaptions.
Of course this is increasingly becoming a moot point, to be honest I get the impression that game developers nowadays increasingly want to make movies, we see less and less gameplay involved in RPGS, and more cinematics being added to action games. One big piece of gaming news right now is hatred over these trends being directed at some lady who proposed them years ago in sounding off about wanting to make "all the gameplay in games skippable" which is alarmingly close to where a lot of things are going.
In a few years it might not matter because your video game might functionally not be all that differant from a movie, and a lot of "gamers" might be people who just watch cartoons sold as games.