name a recent example of a 34 yr old back up who came through for several games

Josh McCown.

Played well for the Bears last year after being a career back-up. Got himself signed by Tampa.

We saw him. McCown was not the reason the Bears lost. Quinn was, which is different.

Despite becoming an unrestricted free agent in 2013, on March 29, McCown signed a one-year deal with the Bears. McCown played in the second half of week 7 against the Washington Redskins after Cutler hurt his groin in the first half. McCown completed 14 of 20 passes for 204 yards and a touchdown to Martellus Bennett, but the Bears lost 45-41. On November 4, McCown led the Bears to a victory over the rival Green Bay Packers on Monday Night Football. McCown threw for 272 yards and 2 touchdowns en route to a 27-20 victory. Cutler started the week ten game against the Detroit Lions, but was replaced by McCown on the final drive due to an ankle injury. McCown guided the Bears to a 74-yard touchdown drive, completing 6 of 9 passes for 62 yards and an 11-yard touchdown to Brandon Marshall. However, the Bears lost 21-19. On November 11, Bears head coach Marc Trestman stated that Cutler is not expected to play the following week against the Baltimore Ravens, and McCown will most likely get the start. McCown started his second game against the Ravens, completing 19 of 31 passes for 216 yards with one touchdown and a 92.9 passer rating in a 23-20 victory. In the last four games, McCown has thrown for 754 yards with five touchdowns, no interceptions and a 100.0 passer rating. From week 6 to week 12 in the 2013 NFL season, McCown had the highest passer rating of any quarterback in the league. McCown started week twelve against St. Louis. Against St. Louis, McCown completed a franchise-record 36 passes for 352 yards, two touchdowns and an interception. The next week against the Minnesota Vikings, McCown threw for a season-high 355 yards, completing 23 of 36 passes for two touchdowns and a 114.9 rating. In week 14 against the Dallas Cowboys, McCown threw for four touchdowns and ran for another while completing 27 of 36 passes for 348 yards and a career-high 141.9 passer rating en route to a 45-28 victory. McCown became the first Bears quarterback to score five touchdowns since Jack Concannon in 1972. McCown was eventually named NFC Player of the Week. McCown ended the 2013 season completing 66.8 of his passes for 1,829 yards with 13 touchdowns, one interception and a 109.0 passer rating, the third highest behind Peyton Manning and Nick Foles,[34] the best in Bears history. On January 24, 2014, McCown was named to the USA Today All-Joe Team. On March 12, 2014, McCown signed a two-year, $10 million contract with the Tampa Bay Buccaneers.