In all honesty, I think it's entirely possible. The main problem with adapting a video game to a movie script is that of course most of it has to be cropped and condensed down in order to fit within a 90 minute or 120 minute running time. I believe it's all about the execution of such, a good example is the Lord of the Rings movies; nobody thought it would be possible to adapt the books to the big screen, it was believed to be impossible. Yet, we ended up getting one of the most critically, financially and fan-loved trilogies of all time. There are definitely stories/concepts within games that would make excellent movies, but the problem is that major studios typically dump the responsibilities of producing, writing and directing onto people who have little to no interest in what they're actually making or they are just too inexperienced and haven't had to tackle the situation of adaptation before. The Lord of the Rings was a huge risk with it's production, and yet it was a passion project by those who'd made it.
That's all it would take really; directors, writers and producers that are competent enough and have a passion for what they're doing. Unfortunately there aren't many movies made today that had a creative vision behind them, now most movies are sequels or soft-reboots that are only made to turn a profit. It still is possible, but unlikely in today's climate of cinema.