Steve McNair was definitely a better QB later in his career but if he's the comp for Russell Wilson then Russ is almost done. McNair played his last season as a 34 yr old. He played in 6 games and averaged 5.4 yds per attempt. He announced his retirement after that season. He's the example of a QB who was washed up "well into his 30s". No shame in that. Most guys are in this league.