Before I get into my take, I'd like to clarify a few things about Roger Ebert, who isn't getting a completely fair take here. It's worth noting that he was one of the early champions of film as art (prior, it was heavily censored by the Hays Code on the basis that it was just a product), as well as film criticism as art (he won the first ever Pulitzer Prize for his field). He also championed Martin Scorsese's work at a time when he was seen as ultraviolent garbage by the prudes of the 70s. Speaking of not being a prude, he also wrote Beyond the Valley of the Dolls and praised Black Dynamite for having nudity. As said earlier, he was an anime fan and pushed for Americans to take it seriously as art. (Note that he never even once questioned if anime was art; it was a given to him.) Yes, he did sometimes complain about explicit content, but he insisted that the context was always the problem. (Compare his negative review of Kick Ass for child abuse with his positive review of Let The Right One In also for portraying child abuse. The former does it just for entertainment, the latter attempts to discuss the problem seriously.) In fact, he wanted the film rating system either abolished or reformed, as he hated that it graded content only and ignored context.
Ebert originally said that video games are not art. He later clarified that he meant "high art", as they obviously contain elements of multimedia art. (Note that multimedia is already a category in art galleries of all levels of pretension.) And that is the real point of contention that ought to be discussed without dismissal on grounds of being elitist (which is itself a pretentious opinion).
I think we could say that games have the potential for high art, but they usually lack the context for it. Gaming is an industry first and foremost, and few corporations take it seriously enough to preserve it as art; sure, iD Software releases source code, but that's about all the commitment we get most of the time. Everyone else guards their IP to the point of killing it (hello, Konami) and making sure that it is unavailable. And there isn't a single soul in the industry calling for lower copyright terms. We barely get any fan game leniency, and this is an industry heavily based in Japan, the land of doujinshi. And even the game makers aren't too keen on calling it art. Shigeru Miyamoto said it's not, and even Hideo "watch my very deep 3 hour cut scene" Kojima said it isn't. That might just be a matter of protecting themselves from criticism (both have faced it from people who reviewed their work properly), but it only undermines the art form's ability to ascend.
What's more, gaming reviews are rarely art reviews; they're just consumer reports. Every critic writes like they just test drove a car instead of like they saw a movie. Try applying the Graphics/Sound/Control/Fun Factor format to a film review, and you'll be laughed off as a childish amateur. But we not only accept this for games, but demand it. Any reviewer that tries a real art review gets screamed at to "just review the gameplay", as treating the low art games like art results in negative reviews. (See serious reviews of Metroid: Other M, Resident Evil 5, and the Tomb Raider reboot.) And that'd be more common than not, as so many games have plots that fall somewhere between Paul WS Anderson quality and "Spielberg is really phoning this one in" quality.
And honestly, despite what they claim, the majority of fans don't really want it to be art. As Ebert said, what they really want is confirmation of their belief that the genre deserves respect. They don't want it reviewed properly, they don't want deeper works that make them think, and they don't want to be told about the ugly side of Call of Duty and other games that look bad when even college freshman-level artistic interpretation is applied to them. What they want is to be told that games are good and that nobody is going to say bad things about the new entry in their favorite series.
And it's a cyclical thing. Fans demand mere entertainment; industry makes mere entertainment; critics have their hands tied and just say "me think game are fun"; fans buy and demand more mere entertainment. And thus the corporate profit motive produces only the product that increases the high score.
Are there games that try to be art? Sure. The indie scene has them. But many of them are questionably "games". Is a visual novel with little or no gameplay a game, or just an illustrated ebook? Is a walking simulator a game, or just a simulator with a narrative? Maybe they are just multimedia art (minus the "game" designation), like the ones in art galleries.
So while we can easily say games are art, the high art status is questionable. Maybe one day game design will advance to the point where it can have it, but it's hard to say it earns it now. And it's going to take cooperation from game makers, critics, and gamers to get there.