Transfer out to compete for a starting job. Let's assume the QB at the new team has done all the right things, everything that coach has ask him to do but the transfer is a better player. Transfer wins the job, potential starter gets butt hurt and claims it was a slap in the face and wasnt giving a fair shot. Potential starter transfer to take another possible starters job who has "waited" their turn...so on and so on.
Fact of life someone is always better than we think we are.