Because it has nothing to do with the quarterback, it has to do with the O line and the play calling. Griese isn't as mobile as Jay and he has had no playing time since pre season. And there is no continuity between Griese and the O.
The O line is terrible. They open no holes and they miss blocks and they allow penetration.
Jay threw a deep pass to DT, right in his hands. What happens, he bobbles it and it is intercepted. That would have put us at least in FG range. Not that it mattered with clutch Mare.
Screen pass to RW was a sure TD. What happens, Bruschi runs him down before he even gets started. Who was responsible to block him?
Jay had two or three passes tipped at the line. Defensive penetration.
Jay was sacked once and had to run for his life on the OT play.
And then there was Mare and the 32 yd avg Turd a Turk