Who says he can't get them there? He's not Brady or Mahomes, but Flacco, Wilson, Eli Manning, Brad Johnson, Trent Dilfer all won Super Bowls. He's in that league for sure. Heck the Bills lost SBs to Jeff Hostetler and Mark Rypien.
You don't throw away Tua when you have nothing else.
What they need to do is improve their defense, especially the coaching.