The race to the degenerate bottom is not steady. On the contrary, it always accelerates; for, it is an arms race.
You can see this with any medium that depends for its survival on the attention of many minds: advertising, entertainment, journalism. All outlets of such media compete with each other for attention. The one that is the most extraordinary wins the competition. So the competition is to discover which outlet is the most abnormal, thus attractive of notice. Whatever was the most abnormal during the last round must be surpassed in the current round in order to gain notice: the most abnormal recent instance resets the bound of normality.