This thing is about power.
When you enter a position of power that was not self-created, it is difficult to manage people who were a product of a previous administration.
I have been in the position myself.
Bo Pelini was Tom Osborne's guy, who fully supported and related to him in a certain way. They had a working relationship and mutual understanding and expectations.
Enter Shawn Eichorst, who only has nominal authority over Pelini because again, he is Tom Osborne's guy. Eichorst is uncomfortable because he was basically handed the keys to a rental building where the tenants have different rules and expectations that he does.
Solution? Get rid of the tenants from the old landlord and fill it with the new ones, who agree to the same rules, so that there is no question about authority.
But how? Politics. Eichorst waited until public sentiment for Pelini was low and then took his chance.
FWIW this is a normal procedure, I expect him to have a great relationship with Mike Riley, because now he has his guy. And I expect him to have one with the players he recruits as well.
It is also to be expected that Pelini is bitter and he will embitter his players toward the AD.
This stuff happens all the time.
Edit- the tricky part is for Mike Riley, who has do clean up after this and deal with some of the embittered players.
That is a hard job. He will have a new staff, so that helps. It will be best if he doesnt hire the existing coaches. I really hope they can come together and play great. I figured that it would take a couple years for the Huskers to rise to prominence again, but now I think it will take about 3 or 4. GBR!