Since I have started watching pro football, here's some of the quarterbacks that have gotten to the Super Bowl (not necessarily won, just got there):
Stan Humphries, Chris Chandler, Steve McNair, Trent Dilfer, Kerry Collins, Brad Johnson, Jake Delhomme, Donovan McNabb, Matt Hasselbeck, Eli Manning, Rex Grossman, Joe Flacco, Jimmy Garoppolo, Cam Newton, Jared Goff, and Nick Foles.
I don't care how much you hate Dak, if you don't think he's better than any of the QB's I listed you just don't know football. The fact Prescott is a better QB than them means the Cowboys only need a moderately better supporting cast and coaching staff than they currently have to get to the big game.
Dak is also better than any QB factually available to the Cowboys for the foreseeable future, so it's up to the coaches and front office to build a team around him that can get it done. There's 16 examples above of lesser QB's with teams that did just that.