Demotion? 3 guys who worked on this staff are now head coaches, getting on this staff is a great career move. You’re much more likely to get interest than if you’re an OC in college.
For how long? Only one of those 3 is having any kind of success. Staley and LaFleur could be on the way out after this season and that leaves only Taylor who people weren't happy with last year but they've turned it up the second half. But lets look at those 3. MLF was Rams OC one year went to the Titans so called plays one year before getting a job. Zac Taylor called plays for 5 games as an interim OC for the Dolphins. Staley was a DC for one season in the NFL and one in college IIRC.
None of the three guys had an NFL resume like Coen can put together going back to Kentucky as OC. A year as McVay's OC plus three years as a position coach for him. He goes back to Kentucky and their offense is good again after a down year without him added to his already quick time with McVay and he would have a better resume than Taylor, LeFluer or Staley two of which likely get fired this year.