Years ago when I was based out of CLE and UA still had a hub there that was actually a very busy route. Sad what has happened to CLE with UA. I still travel there a couple times a year and it is indeed getting tougher and tougher to get direct flights in. Also many flights are now UX CRJ's (DEN-CLE, Uggghhh).
I have heard that UA is not releasing the unused gates in CLE that they lease so that competition can't come in. They supposedly got some sweetheart deal and feel it is probably better for them to pay the rent on them than release them to new competition out of CLE.