Er, wasn't there like a 4 game stretch where he didn't just not ball out, he played poorly, not even "game manager" level. It might've just been one or two games of that, but I recall there being a stretch where the media was really hammering the "is Purdy holding back the 49ers?"
MVP is popularity contest shit and politics. I'd say Josh Allen is more important to the Bills success than Jackson is to the Ravens (because the latter has a more competent overall team, better coaching). And for the regular season, I'd say both are more important to their teams than Mahomes is. And yet, literally no one in the entire league, including Harbaugh no matter what that a-hole says, would take either of those guys over Mahomes in the playoffs, because well 3 rings to none. I think Purdy is less important to the 49ers success than any of those, He probably isn't even top 5 (Allen, Jackson, Mahomes, Hurts, Burrow), but probabaly in the mix for 5-10 with guys that are good but on teams that underperform (Chargers, Dolphins, Cowboys, Rams; I'd probably put him here at the moment) and not enough data (Stroud, Love).
Purdy will certainly get paid very well. And then the 49ers will probably trade him away because they'll be in cap hell and if he can't get that roster a ring then they'll decide they need to find someone that can. I won't be surprised if there's some bonkers thing that happens (they trade Purdy and then sign Rodgers or even Brady comes out of retirement for one year deals, maybe trade Purdy for Stafford with the Rams for a similar "let's go for broke before we gotta change"), and the 49ers will draft a QB to reset the "win by leveraging a cheap rooking contract" plan. I predict that if they don't win Super Bowl this year, Purdy and/or Shanahan will be gone. I'd laugh if they get Belicheck and Brady. Maybe they'd go for Carroll, or try to bring Jim Harbaugh back.