He got in based on 1 game. There are many QB's with better stats and careers that never got in. Jim Plunkett won 2 Super Bowls and has better stats playing in roughly the same era and is not in.
Plunkett was great in college. The Patriots stunk when he joined them and he got hammered.
By the time he was with Oakland he was a shell of his former self but did a good job.
He had a really good arm in college. By the end not too good.
It was a shame he got drafted by the Pats.