I feel like, unfortunately, consumers are partially to blame for this. We all say we want a grading company that grades fairly, but then patronize the ones that are more likely to give higher grades for personal gain. I guess this is just being a normal human being, like, it's hard to expect anyone to behave differently, but these companies know that higher grades mean higher sales (for everyone) regardless of accuracy.
Same thing in card grading. If I have a card that I believe is gem mint 10, I might sub grade with BGS. However, it's much safer for me to submit to PSA and get a 10 (9 at worst) knowing the card value will be retained better than getting a 9 or even 9.5 at BGS.
And I guess this is where we run into the worst problem with grading. It's bad to have steep grading variance within one company, and having that same variance between different companies just muddies the water even more.
They shouldn't be changing their grading criteria, but they obviously are, and haven't made that public. I grade through WATA so all my sealed games look the same, but damn, this makes me want to swap everything back to VGA. They still seem to be the most consistent with not changing their grading parameters.