The first time the Cowboys ran together two similar successful consecutive seasons without a deeper run in the playoffs was 1968 and 1969.
We went 12-2 and 11-2-1 respectively losing in 1st round of playoffs both times to the Browns .The difference is we had just come off two NFL title losses to Packers and would reach the Super Bowl the following 2 seasons.
The Cowboys have had several other similar consecutive 12 win or double digit consecutive seasons but they produced much success in the playoffs .
1977 &1978 consecutive 12 win seasons resulted in 2 SB appearances.
1980 & 1981 consecutive 12 win seasons resulted in 2 NFC champ appearances
1992 , 1993, 1994, 1995 4 consecutive 12+ win seasons resulted in 4 champ game appearances and 3 Super Bowls
Cowboys also had 3 double digit win season from 1970-1973 which resulted in 4 consecutive NFC Champ games and 2 Super Bowls
1975-1981 Cowboys had 7 consecutive double digit win season which resulted in 5 NFC Champ game appearances and 3 Super Bowls.
We shall see what the next couple seasons bring us but if we don’t have any more success in the playoffs this could be the most successful regular season team in Cowboys history without advancing further in the playoffs.
https://en.m.wikipedia.org/wiki/List_of_Dallas_Cowboys_seasons