Using metacritic as a reason not to use 5 as average makes no sense. No publication should feel obligated to whatever metacritic feels is an average score.

They shouldn't feel obligated but reality probably means that some publications are afraid to go against the grain.  

People often talk about "click-bait" and websites using low scores to draw viewers but I'd guess that established publications feel a lot more pressure to bump up scores.  In fact, it would be my guess that there are more inflated scores than deflated scores on Metacritic.  It's a much smarter practice in the long term.

What if a website that scores 70-level games on Metacritic as 50-level?  That might not be so bad--but what if they scored a 90-level game at the 70-level?  What if BotW or TLoU showed up with a 75?  It wouldn't even matter if they explained their scale on their website, the backlash would be instant and vicious.  Besides that, they'd certainly earn the "biased" label with many fans, even if they were fair across the board.  Most likely, even some of the people arguing that 50 should be average would be outraged if their favorite flagship got less than an 80.

I can say without doubt that I'd adjust the scores for such a reason if I felt it necessary for the security and continued existence of my business.

5 should be the average because the score at the end shouldn't hold much weight, that's what the review should be there for. The 1/10, 5/10, 8/10 should just be a vague summary of how they feel about the game, really it shouldn't be there at all.

That's on fans who place way too much weight on a game's metascore. People were throwing fits even here when Breath of the Wild fell a whole point to 97 after a few slightly lower scores for it came through, as if it made any actual difference. You might be correct on some sites giving games higher scores because they fear a backlash, but I find it rather appalling that a sites or reviewers integrity is lost simply because some "fans" feelings might be hurt. Getting angry at review scores in general is such an amazingly childish thing to do anyway

There is only one way to weigh the average review score of videogames: the sum of all videogame review scores divided by the amount of videogame reviews. I think you'd end up somewhere around 65-70.

5 is perfect for that because it's in the middle. 7 is misleading.

I grew up using a system where 7 or 7.5 was average, but I can see the obvious reason why people would go with 5. I’d say meet halfway, and use 6 or 6.25 lol

Yeah this makes sense. 7 is almost always just average, not only for video games, but in general.

5, that would mean I only enjoyed roughly half the aspects of the game, why would that represent average? If I only enjoyed half of what the game offered I would hope that is below the games I play on average.

"Average" isn't an attribute a number has. It's the result of a calculation. With today's games most reviewd are around a 7 so that's the average. A game doesn't get a 7 because the reviewer thinks it's average. It gets that number because it ticks certain check boxes for a certain quality.

If you reviewed every single game in existence, then the average score would most likely drop considerably, maybe even below 5. So "an average game" basically has only meaning in a certain context and is not a fixed number.

"Average" isn't an opinion, it's not what a game or a score "should" be. It's simply what it is in a certain context. To say that the average should be 7 or 5 is just plain stupid. I mean why would anyone want the average to be 5? Shouldn't we want the average to be much higher?