Work in progress, but looking at Cowboys history, there are moments that mark the changing of eras from one to the next. The Bobble is one of them.
1960 - 1971, Next Year's Champions Era: Cowboys join NFL
1971 - 1979, America's Team (or Doomsday) Era: Winning Super Bowl VI
1979 - 1985, So Close, Yet So Far Era: Staubach's Retirement
1985 - 1989, The Pathetic Era I: Dickerson's Record Playoff Game
1989 - 1999, The Dynasty: Jerry Jones buys Cowboys
1999 - 2006, The Pathetic Era II: Michael Irvin's injury at Veterans
2006 - Present, The Are You Entertained Era: The Bobble
If the Cowboys win a Super Bowl this year or in next couple years, I'd consider Garrett's replacement as the end of the 'Are You Entertained Era' in 2019.