I never said the whole lot is garbage. But a huge portion of them are at best passable or forgettable.

Average time played is not a good metric because people on both extremes will skew it heavily, like any average - people who bought the game but never played it, or people who play it way too much. It also depends a lot on the game. On an okay-ish game that has a +/-20h campaign will be pretty easy to munch through just to check it off, but one can easily abandon an okay-ish game with 5-10 minute matches after a handful of hours.