I think the big problem is that game critics buy into hype WAY MORE than film critics. But film critics aren't perfect either. They have their own snobbish elitist arthouse bias. Movies that are intended to be low-brow but do a great job of being what it's intended to be (a fun low-brow movie) are often given shitty ratings (ie. 1-2 stars) because the reviewer itself has a bias in favor of the artsy high-brow stuff. A big reason for this I think has to do with the immaturity and low emotional intelligence of the average 'hardcore gamer' compared to the average movie buff IMO. Whenever a game reviewer gives a 'controversial' score for a game, you see fanboys rage on internet forums, call the reviewer all sorts of nasty things, pester the reviewer with hate mail, etc. It's no wonder society perceives hardcore gamers to be losers. Movie review readers tend to conduct themselves with a lot more maturity and class than hardcore gamers. These kind of hate-on backlashes probably have a lot to do with reviewers giving out inflated scores.
At the end of the day, it's all about opinion. There is no point in reviewers pretending to be objective because they're not supposed to be objective. This is why I don't rip into reviewers (like many fanboys do) when a reviewer gives a game I like a low score. For eg. If a reviewer wants to downgrade an Ace Attorney game because it "doesn't have a lot of real gameplay" (I've seen this used a lot when reviewing visual novels), fine. I strongly disagree with this view but I respect their opinion and the diversity of opinions you see among the many different reviewers listed on metacritic. A game like Ace Attorney isn't for everyone. And I think gamers have a right to know that when they read reviews. If I wrote a fanboy-esque review of the game, giving it a 10/10 and not pointing out things about the game that many people may find annoying (ie. the mainstream gamer), who am I helping? I'm just preaching to the choir (like-minded Ace Attorney fanboys like me). I'm not doing anything of positive benefit to gamers this way except make a lot of like-minded fanboys feel bigger in the pants.
I would like to see the scale be more like the ones film critics use (where 50%, 2/4, 2.5/5 is average) to prevent out of control score inflation. But hey, it's not a big deal. What I'm more concerned about is this whole idea people promote that reviews need to "objective". That is bullshit. Yes, you shouldn't write outright factual lies in the article (ie. saying that the game doesn't have so-and-so feature when really it does) but there's going to be a lot of subjectivity involved in giving a review. That's the reality. I may feel that a particular game is a great game but my reasons for thinking it's a great game may very well be reasons for disliking the game to another person.