It's a matter of historical perspective. Top scoring offenses don't make it back the big game without a top defense.
Take the Packers. For the past 25 years, they have had a top 10 offense in scoring for 18 of those years. 3 Super Bowl appearances. When their defense was 1, 5, and 2 in scoring. Outside those 3 years, the Packers defense averages 15th in PPG.
Saints: Top 10 offense 11 of 13 years since Brees has been there. Average Defense rank. 20. Granted they won a Super Bowl, But they haven't done much since then.
Broncos' Elway's last 5 years. Top 10 offense. It wasn't until they had a top 10 defense that they won the Super Bowl.
Broncos. Manning. 4 years. The offense went 2, 1, 2, 19. The defense went 4, 16, 22, 4. It was that 19 and 4 years they won.
Patriots. Brady era. Top 10 offense 16 of 18 years. Top 10 defense 15 of 18 years. Super Bowl wins when the defense was 6, 1, 2, 8 and 7 in ppg.
Now, is it possible to win the Super Bowl without a top 10 defense? Yes. The Giants and Saint have done it in the recent past. But if you want your team to continue to go back and become a dynasty, then it needs to consistent year in and year out.
So please, go on thinking that the offense can do it by themselves. BTW, When the Rams won the Super Bowl, their offense was number 1, but their defense was number 4.