The scandalous characters in David Lodge's Changing Places, Small World and Nice Work amuse the public because their actions are assumed to be implausible and fundamentally false; the world of these fictions is comic because it represents the absurd as normal. Similarly, Sharp's Porterhouse Blue is funny for those outside Cambridge because it obviously is and must be too ludicrous for accuracy.
A minority of readers will have an entirely different different view. The experienced academic is entertained (no more) by these works because they represent tedious everyday reality as if it were a comic fantasy.