For starters, user reviews are a horrible measure since people give one's for silly, inane reasons such as to "counter all the tens".
But I don't think reviewers are corrupt, just that they use a horrible reviewing method. This "-out of 10" or "-out of 100" method just doesn't work because people tend towards a grade-school "80 percent is average, 70 is poor, 90 is great" system that leads to games being horrendously misrepresented. With only four points of the scale ever actually in use, you get cases where the different between a terrible game and a decent one is as small as one point, or the different between a "meh" and a GOTY only 10%. You rarely see a 6/10 on triple-A games since big name reviewers don't want to generate any controversy despite the face that 6/10 should be considered above-average, and this leads to game review scores getting inflated to the point they no longer matter.
But I don't think reviewers are corrupt, just that they use a horrible reviewing method. This "-out of 10" or "-out of 100" method just doesn't work because people tend towards a grade-school "80 percent is average, 70 is poor, 90 is great" system that leads to games being horrendously misrepresented. With only four points of the scale ever actually in use, you get cases where the different between a terrible game and a decent one is as small as one point, or the different between a "meh" and a GOTY only 10%. You rarely see a 6/10 on triple-A games since big name reviewers don't want to generate any controversy despite the face that 6/10 should be considered above-average, and this leads to game review scores getting inflated to the point they no longer matter.