LOTS of things had to happen this past season to win the SB, which is why very little number of teams ever repeat. Saying that anything is close to being "guaranteed" is just silly. Barring catastrophic injury at important positions, they should be able to compete in the postseason again, but even that certainly isn't guaranteed.
For example--
1) they had to stay very healthy, something that we haven't seen at all lately
2) they had to come back from THREE postseason double digit deficits, something with an extremely low chance of ever happening
3) they were the first team in 30 Super Bowls who shook off a 10+ pt deficit in the 4th quarter, as the record prior to Sunday was 0-29
4) there were approximately 100+ passes thrown in the NFL this season from the one yard line, and NONE of them were intercepted. Even taking the Malcolm Butler INT into account, there was less than a 1% chance of us picking that pass off to win the game
5) staying in the same vein, we needed a good amount of luck to win the SB (something that we certainly have been lacking in the big game lately)