I mean ok some nights do bang it from 8pm just ask some of my regulars lol but yeah it seems to be hard for any dj to get a break through but in the scene we have in the uk you have to have some variation within your set or even be able to warm up for the headliners.
I run nights with guests & residents but i also have nights where its just up & coming dj's and two residents to give new blood a chance and let the ressies get the opportunity of a peak time slot! but not many ppl do that