Here's a spiel I've done a few times on the subject. Oddly, you're generally arguing philosophy in a weird way.
Flipping gears a little:
Question: Is X perfect?
Define perfect: Without flaw.
Define flaw: A fault (esp. in design.)
Basically, you wind up in a long, protracted debate on whether or not a flaw can exist without context and without purpose. Followed by whether or not a flaw can exist without similar context, etc. It becomes a debate about abstract concepts.
To avoid the religious: Would a perfect food be something that would provide for a person's entire lifetime of meals so they never had to eat again? It would serve the nutritional purpose, but also render itself useless in one shot. Or would it be something that tastes so good that you couldn't stop eating, yet filled you up not at all so you could continue eating it forever? Thereby serving little purpose, save the purpose of being eaten, which it would do better than anything before it.
Not looking for an answer, but it's the same spiel:
Define art.
There are two answers I've found.
1) dictionary: the quality, production, expression, or realm, according to aesthetic principles, of what is beautiful, appealing, or of more than ordinary significance.
In which case, yes. Games are art, or at least a few of the extraordinary ones are.
2) Personal: An emergent property or quality of a piece, accomplishment or skill that registers emotionally beyond the learned skill (though requiring great skill) required to perform or create it. There's a permanence argument in here, as well as an understanding of this being a profoundly personal or cultural thing.
If you've ever been reduced to tears or felt a swell of pride by a song, a dance or a kata, you understand this.
I would argue, then, that intentional manipulations don't count, nor do jump scares, or anything that can be put to a chart and learned. As such, I personally believe that acting, music, drawings, etc. up to and including the finished products of movies, books and games - all things with artistic merit - are actually artisan work, not art. They are created more or less on command and become the livelihood of the people who create them.
That is not to say that some of these pieces don't achieve the level of art, but that the lump sum is created as something else. Just the same, as a rule, I don't tend to consider most things I could buy in a store as 'art.'
Journey, actually, I'd argue is a game created to be art, or at least with effort made to that effect. Check out Extra Credits' video on it for some good insight, but the short version is that they did most of the monomyth properly, which is rare, and made the player play through most of it without realizing. The second playthrough stuff is impressive.
MGS is something of a bad example most because the biggest complaint to be levied against it is that it's really not something that should be defined as a video game, but is trying much harder to be a movie. The 'joint medium' thing is something many people would argue as an artistic endeavor.
Honestly, Skyrim would be your better example. Enjoy the game all you want, and I for one love it for what I'm about to say, but the core arguments of the creator's vision hits hardest in games like that. Little Big Planet is much the same. In both, though at different times, there's neither a solid narrative nor a pure simplicity (IE: Tetris) to the goings on. Add in the modding community and your have an intentionally half-finished picture to scribble on.
Final Fantasy 2/4 and 7 can be argued as having weak narratives and a slipshod setup due to the whole 'plot death' thing that betrays the mechanics of the world as established and can be argued as the worst version of deus ex machine, and so are of little to no merit due to unfair manipulations.
Games like Thief, or even older Marios, can be argued as having no true merit within real-life experience because of the save options and that death isn't final, or even real, robbing it of any emotional or artistic weight. Actually, the only game I can think of right now where those deaths are actually in-narrative is Dark Souls.
Again to Super Mario, especially 3 and World, can be argued as having no true or cohesive narrative since each level is self-contained and has no importance to the overall game as reaching the 'end boss' at any time and under any circumstances yield the same ending/resolution.