In my personal view, the PC gaming scene has grown-up along with its community. The major publishers left the PC because it was easier to develop and sell no-brainer platform/fps/driving games on consoles that cater for younger audience.
When you look at the PC gaming magazines, cross-console games have faired worse in reviews since the reviewers have also matured like cheddar. The games that consistently win the top awards or above 85% are those designed for gamers who have been around the block (including myself) for sometime - Total War series, CoD, Dawn of War, Armed Assault, Witcher, Fallout series, Warcraft/Starcraft - These are games that have succeeded on the PC but probably would fail on console.
At the moment, the rise of indie games and free-to-play mmo is giving the PC a new lease of life. When Starcraft II broke records for number of sales on release, it must have awaken the rest of the gaming publishers who have neglected PC.
As a side note, are console games developed on PC? I'm sure majority of them use the Gamebryo engine, as used by Oblivion, Civilisation 4/5, etc?