Even when things are running smoothly, a 30 minute delay out of DXB is not at all uncommon. I must have had one flight in the last 10 that actually departed on time out of DXB. There's usually enough of a margin to make up time. One of the reasons this happens is because at DXB, EK can do whatever it wants in terms of slots. But traffic is high at peak times, which adds to delays.

At outstations, it is a bigger problem being late as EK doesn't get any priority over other airlines, and probably need to pay for sitting on the ground longer, so it's more important being on time.

Connections do play a role, depending on how many pax are connecting. My father was on a DXB-CGK flight last year that was delayed 3 hours because almost half the pax were connecting from Saudi and the incoming was late.