Pinside's rating standards are bunk...there you have it. My guess is the major manufacturers, as well as owners try to skew their ratings to increase the sales and market value of their games.
Is there a solution that fits? One way to eliminate this rigging of the system is to eliminate machines that have 500 verified ratings or less. To be fair, those with under 500 ratings could be included in an "Up and Coming" list.
Let a machine be thoroughly vetted before be rated against a machine that has been thoroughly vetted.