The length of the '60's into the '80's run made it difficult to define. It began with the Packers being the hurdle, then the Steelers, then the 49'ers. All were great teams. The Cowboys were a little young when they lost to the Packers, then suffered a hangover from those defeats. They broke through with the Super Bowl win over the Dolphins and maybe underachieved for a few years. The team that beat the Broncos in the Super Bowl was probably Landry's best.
I think the Cowboys were a kind of dynasty during those Landry years. They needed to win at least a couple more Super Bowls to be classed as one the way it is defined these days. But it was a dynastic organization. It's a shame Staubach didn't get to quarterback the team that lost to the Colts in 1970. The Cowboys almost certainly would have won that one.
I enjoyed the Landry teams because the same players were together so long. You knew the linebackers were Jordan, Howley and Edwards. For a long time, the DL was Lilly, Andrie, Pugh and either Cole or Townes. The OL was stable. Renfro, Cornell, Harris, Waters... Garrison and Newhouse. Drew, Hayes, Tony Hill... on and on. These were "our guys." There were deep links from the earliest to the latest years.
The 90's was pure rocket fuel and much closer to the Steelers' run -- lightning in a bottle, An all-time great kind of run.
I enjoyed them both in different ways. You like Southern Comfort or Jose Cuervo?