[fullmetal]

Don't weight the run/pass ratio too heavily.  When the run is abysmal on first and second down, you almost guarantee a pass on third down.  If you're relatively successful running on first or second down, you can pass a lot less often.  Defenses certainly know that passes are more likely in third-and-long situations...

But yeah, there are many factors involved.  I would say the collapse of the run game is the primary issue, and that leads back to OL/FB blocking.

[fullmetal]

Don't weight the run/pass ratio too heavily.  When the run is abysmal on first and second down, you almost guarantee a pass on third down.  If you're relatively successful running on first or second down, you can pass a lot less often.  Defenses certainly know that passes are more likely in third-and-long situations...

But yeah, there are many factors involved.  I would say the collapse of the run game is the primary issue, and that leads back to OL/FB blocking.