Its still not worth the absurd contract. Because
a) No one knows if that was a luck streak a la Flacco or the book of Eli who had two of them (btw, the active Int king, the worst long time starter of his/this passing-friendly era, maybe ever). No one can look in the future. It was tried before, it was always a fail.
b) This 20+ millions per year eat up approx 15% of cap money. For one unproven player… I think I read it here: QBs are 20% of offense (?). So 10% of offense and defense. And even less if we calc the special teams into it. Maybe 7% then = a proven QB should cost your team 10/11 mill per year… Dumb front offices. They pay too much for the QBs. Thats why they cant pay the other players. Thats why (next to other reasons) defense prevails in the end. Even with obscure guys like Dilf Dilfer…

https://www.pro-football-reference.com/play-index/drive_finder.cgi?request=1&year_min=2017&year_max=2017&team_id=sfo&game_type=R&game_num_min=0&game_num_max=99&week_num_min=13&week_num_max=17&start_event%5B%5D=Downs&start_event%5B%5D=Interception&start_event%5B%5D=Punt&start_event%5B%5D=Blocked+FG&start_event%5B%5D=Missed+FG&start_event%5B%5D=Fumble&start_event%5B%5D=Muffed+Punt&start_event%5B%5D=Blocked+Punt&start_event%5B%5D=Kickoff&start_event%5B%5D=Onside+Kick&start_event%5B%5D=Own+Kickoff&start_event%5B%5D=Muffed+Kickoff&end_event%5B%5D=Touchdown&end_event%5B%5D=Field+Goal&end_event%5B%5D=Missed+FG&end_event%5B%5D=Fumble&end_event%5B%5D=Interception&end_event%5B%5D=Downs&end_event%5B%5D=Punt&end_event%5B%5D=Blocked+Punt&end_event%5B%5D=Blocked+FG&end_event%5B%5D=Safety&end_event%5B%5D=End+of+Half&end_event%5B%5D=End+of+Game&exclude_kneels=1&drive_st_gtlt=lt&drive_st_own_opp=Own&drive_end_gtlt=lt&drive_end_own_opp=Own&drive_num_gtlt=gt&start_quarter%5B%5D=1&start_quarter%5B%5D=2&start_quarter%5B%5D=3&start_quarter%5B%5D=4&start_quarter%5B%5D=5&end_quarter%5B%5D=1&end_quarter%5B%5D=2&end_quarter%5B%5D=3&end_quarter%5B%5D=4&end_quarter%5B%5D=5&tr_gtlt=lt&minutes=15&seconds=0

That’s a +11 difference between “good drives” and “bad drives”. Since 1970, just 10 teams have had a +10 difference over 5 games, and it’s pretty much exclusively a list of HOF QBs and/or historically great offenses:

The 2016 Falcons, 2015 Steelers, 2014 Packers, 2013 Broncos, 2011 Saints, 2007 Patriots, 2005 Colts, 2000 Rams, 1994 49ers, and 1982 Chargers.