Disagree. To me, a dynasty is a team that wins multiple championships (3+) in a short period of time with basically the same players. You're putting your thumb on the scale when you include the early 80's teams under Landry.
You have to, IMO, when you are judging Landry's Cowboys. He went to the Superbowl with two different QB's and and competed in the NFCC with four QB's over a stretch of two decades where you have teams with overlapping rosters. Many of Meredith and Morton's players carried over under Staubach and likewise Staubach's players competed under White into the 80's.
That's a dynasty, excellence over time with some thread of continuity from year to year. You couldn't for example include the Steelers with Roethlisberger and Bradshaw because nothing links them together.
By your definition you can't then include both Montana and Young with the 49ers because there is zero continuity, all but no players or coaches, between the 1981 and 1994 teams. Is that both thumbs on the scale? But when you consider there were several overlapping players like Jerry Rice and Randy Cross between both QB's it makes sense.
I agree you can choose to define it different ways, and it's subjective.
It's clear the writer of that article chose to define his own (Landry, Montana-Young, 1940's, etc). I'm trying to rank within his own definitions
