The heyday was in the early-mid nineties, Universities could not cope with the number of archaeology applicants and, after Time Team, there was a slew of archaeology TV, culminating with the shark-jumping 'Extreme Archaeology'. The reason for this? The kids were listening to the Levellers and Ozric Tentacles plus the pseudo-mysticism of the travelling rave scene and, basically, a fashion for 'dreadlocks and army boots' which in turn lead to an interest in ancient sites and thus archaeology...
There was so much archaology on TV that the BBC put a blanket ban on commissioning new archaeological show, which is why, when Coast was pitched, they neglected to tell anyone at the BBC that half the presenters where archaeologists and about 70% of the focus would, actually, be on history/archeaology. And they got away with it.
In more recent year's there has been a decline in 'homegrown' archaeology programming and, it seems to me, they've even slowed down making endless documentaries about Atlantis/Minoans/The Last of the Lost Missing Unknown Pharoahs and such (unless you go to cable, and even there there are less woo-woo aliens built Carnac shows than there were).
(Most of this stuff was gleaned from an Archaeology in the Media seminar I attended about three years ago which featured talks by Time Team's Tim Taylor (as I mentioned earlier) and laughing snowman Mark Horton.)