Are you just wanting to argue? Cousins was the starting point guard on his high school state championship team. He led his team in scoring, assist, and steals.
What is Kruger suppose to do? They practice 6 days a week for 3+ hours per. Kruger told his players for months that no starting job was guaranteed. He told them that everyone was starting out even and the starters would have to earn their spots.
Cousins was clearly the best player early on. It wasn't close. Cousins was bigger, stronger, faster. He was the better ball handler and the better shooter and the better defender. Cousins has a talent and ceiling that far exceeds Grooms. A coach can't say one thing then do another and have credibility with his team.
As the season wore along Gooms replaced Cousins after Hornbeak briefly replaced Cousins. Buddy replaced Honrbeak as a starter. There is nothing curious about that at all. Players evolve, devolve, plateau, peak, and stagnate continually through a long season. When Kruger made the call at the beginning of the season, it was the right call and there wasn't anything fishy about it.