Montana played during a 14 year winning streak of the NFC over the AFC. All of the best teams were in the NFC. If he played in the AFC in that era and nothing else changed, he’d likely have made it to the Super Bowl a lot more but would have gotten spanked by the Giants, Cowboys, Redskins, etc. a few times as well.
This is like LeBron right now. He’s been in the finals 7 years in a row and has three rings. If he were in the West he might have a perfect 3-0 Finals record.