@theclaw
Researching the Bator Rule during past playoffs, I found NO other pure-play Bator Rule situations so this situation is unique.
Closest I found were 4 past Superbowls in which 3 of the 4 parameters were met (parameters being to bet against any team that scores 30+ while holding opponents to 10 or less in two consecutive games):
1990 SuperBowl: SF defeated MIN 41-13 and RAMS 30-3. Bet against SF. Result: SF defeated DEN 55-10. The Bator Rule loses.
1992: WAS defeated ATL 24-7 and DET 41-10. Bet against WAS. Result: WAS defeated BUF 37-24. The Bator Rule loses.
2001: NYG defeat PHI 20-10 snd MIN 41-0. Bet against NYG. Result: NYG lost to BAL 7-34. The Bator Rule wins.
2018: PHI defeats ATL 15-10 and MIN 38-7. Bet against PHI. Result: PHI defeated PATS 41-33. The Bator Rule loses.
I was hoping for a better correlation and altho these are not pure Bator Rule situations, they don't follow the expected pattern. In fact they trend toward the opposite and are more in agreement with your speciulation that regression is less likely as teams build up to the superbowl. In fact, it may be more supportive of an Eagle victory. The 4 games displayed above represent some of the best superbowl teams in history.
...The '89 49ers were a juggernaut, The '91 Skins team was named the BEST team by Foxsports, the Ravens set the NFL for fewest points allowed in a season, and even the 2017 Eagles rank 36th all-time best team in NFL top 100.
So I'm inclined to view the 7 points allowed in 2 consecutive games by the Eagles to be something rarely achieved. The only better defensive effort in the playoffs may be the 1985 Bears... They first defeated CHI 21-0 and RAMS 24-0 - then destroyed the Patriots 46-10 in the Superbowl.