Disparity in the TV cricket commentary box

Is there disparity in the television cricket commentary box where there seems to be an over emphasis laid on English commentators.

The two Sri Lankan commentators Russel Arnold and Roshan Abeysinghe have being overlooked for most part of the day and there have been a number of occasions during the ongoing first Test between Sri Lanka and England at Galle where none of them have been slotted in for any commentaries for an entire session of play.

This disparity was also evident during the home series whenever India plays where Indian commentators are given preference over the host country commentators.

Is this happening because the host country Sri Lanka does not have its own producers?