Repost from 2012...
Nothing like it has ever come close to happening either before or since.
Somebody in the Landry parade thread responded to a post I'd made about the consistency with which Landry's offenses and defenses ranked in the Top 10 every year, by attributing all the Top 10 finishes to the fact that free agency and the salary cap did not yet exist.
So I decided to look at the entire history of professional football to see which teams were able to put together consecutive seasons in which both their offense and defense ranked in the Top 10 in their league (whatever league it was) in both scoring and total yards.
To adjust for era, I applied the "Top 10" of Landry's era as a top percentage of the teams in the league for other eras.
In 1970, the AFL-NFL merger resulted in a 26-team league. Both Landry's offense and defense were Top 10 in yards and scoring every year from 1970-1978. That put them in the top 38.5% of the league, so using the top 38.5% as the cutoff point, here are the equivalents to the 70's "Top 10" for the different eras, based on the number of teams in the league:
1991-present: Top 12
1976-1990: Top 11
1970-76: Top 10
1969: Top 6
1955-1969: Top 5 (AFL Top 3)
before 1955: Top 4
The Cowboys' rankings in 1968 and 1969 (the lowest was 4th) were also equivalent to a 70's "Top 10," so Landry's offense and defense were Top 10 (or top 38.5% of the league) in yards and scoring for 11 consecutive seasons (1968-1978).
Nothing like that has ever come close to happening either before or since.
Landry's team did it 11 straight times, and no other coach has had a team that did it more than 4 straight times.
History of Professional Football (1920-present)
Consecutive seasons with both offense and defense ranked in the Top 10 in both scoring and total yards.
11 Landry, Cowboys (NFL, 1968-78)
4 Belichick, Patriots (NFL, 2006-09)
3 Brown, Browns (AAFC, 1946-48)
3 Grant, Vikings (NFL, 1974-76)
3 Halas, Bears (NFL, 1926-28)
3 Holmgren, Packers (NFL, 1996-98)
3 Noll, Steelers (NFL, 1974-76)
3 Seifert, 49ers (NFL, 1989-91 and 1994-96)
3 Shanahan, Broncos (NFL, 1996-98)
3 Shula, Dolphins (NFL, 1971-73)
3 Walsh, 49ers (NFL, 1986-88)
The Rams and Raiders had runs of 3 straight seasons, but in both cases it was done with two different coaches. 21 of the 32 teams in the league have never had as many as 3 straight years with both offense and defense ranked in the Top 10 in both scoring and total yards, no matter who the coaches were.
And Landry's Cowboys did it 11 seasons in a row.
Anybody who can remember even one of those seasons saw a part of something that will never happen again.