Dak is a good QB. Not a great one. He has skill. He has talent.
I've been saying this for years now, Dak's problem is that he does not process information quickly. This is why you see him focusing on one side of the field all the time, even while recievers are running downfield uncovered on the other side. Early on in his career, he couldn't read a defense to save his soul. He has gotten better at that every year. But even so, there is only so much data that he can process during a play, and it is obvious to anyone that cares to look.
Can he win it all? Hell, yes. I mean, if Trent Dilfer can ride a defense to a Lombardi, Dak sure can too. And Dak will help the effort a LOT more than a Trent Dilfer ever could.
Side note: Watching the defense completely not show up against the Packers this year was heartbreaking. I will forever blame the Head Coaching interview process for this. There should be a FREEZE on all coaching changes from the end of the season until 2 weeks after the Super Bowl. No firings. No interviews. No offers. No hiring.