[2006alum]

Name a coach not named Saban or Dabo who has been a coach at a single college for more than 6 years who hasn't had a down cycle and at least one mediocre season or losing season?

Gary Patterson was 4-8 in 2013 then 12-1 in 2014. Back down to 6-7 in 2016 and up to 11-3 in 2017.
Kirk Ferentz had great success in the early years at Iowa then a losing season of 4-8 in 2012 before rebounding to 12-2 in 2015.
Mike Gundy went 12-1 and won the Fiesta Bowl (ouch, I know) in 2011. His teams since then have never had a losing record, though several were 6-6.
Kyle Whittingham's teams struggled early on in the Pac 12, but are now annual contenders.
Mark Dantonio was 3-9 in 2016 and rebounded to 10-3 the next season.
Pat Fitzgerald's teams also have been up and down. Same with Ken Niumatalolo at Navy.
Brian Kelly was 4-8 in 2016 and followed up with 10-3 and 12-1 the next two seasons.
Gus Malzahn has never had a losing season at Auburn. But any year in which he does not beat Alabama is a down year.

And it's striking to note that in the past 7 recruiting cycles, none of Alabama, Clemson, or Auburn has had a single recruiting year where their recruiting class was ranked lower than 13th; about half the time all three are in the top ten, with Clemson or Auburn settling at 10th-13th every other year or so. That kind of consistency in recruits year after year gives you lots of insurance against insurance, unexpected duds, etc. Shaw has never been able to count on that, and so his ability to avoid down seasons is even more a testament to the program he's built.

[2006alum]

Name a coach not named Saban or Dabo who has been a coach at a single college for more than 6 years who hasn't had a down cycle and at least one mediocre season or losing season?

Gary Patterson was 4-8 in 2013 then 12-1 in 2014. Back down to 6-7 in 2016 and up to 11-3 in 2017.
Kirk Ferentz had great success in the early years at Iowa then a losing season of 4-8 in 2012 before rebounding to 12-2 in 2015.
Mike Gundy went 12-1 and won the Fiesta Bowl (ouch, I know) in 2011. His teams since then have never had a losing record, though several were 6-6.
Kyle Whittingham's teams struggled early on in the Pac 12, but are now annual contenders.
Mark Dantonio was 3-9 in 2016 and rebounded to 10-3 the next season.
Pat Fitzgerald's teams also have been up and down. Same with Ken Niumatalolo at Navy.
Brian Kelly was 4-8 in 2016 and followed up with 10-3 and 12-1 the next two seasons.
Gus Malzahn has never had a losing season at Auburn. But any year in which he does not beat Alabama is a down year.

And it's striking to note that in the past 7 recruiting cycles, none of Alabama, Clemson, or Auburn has had a single recruiting year where their recruiting class was ranked lower than 13th; about half the time all three are in the top ten, with Clemson or Auburn settling at 10th-13th every other year or so. That kind of consistency in recruits year after year gives you lots of insurance against insurance, unexpected duds, etc. Shaw has never been able to count on that, and so his ability to avoid down seasons is even more a testament to the program he's built.