Henry Brooke's The Fool of Quality (1770) illustrates why the novel needed rescuing. This story stretches to five volumes, has a repetitive central plot (in which each 'villain' is humbled and reformed, becoming the 'hero' of the next section), and depends continually on coincidences and providential deliverances. There are digressions on the importance of commerce, the status of women, the British constitution and the use of prisons. There is much sobbing.
For an example of the state of the novel even when Jane Austen was writing, take The Nuns of the Desert by Eugenia de Acton (1805). We have Brimo, a talking dog, who answers questions put by witches. This is bunglingly explained later as ventriloquism. It is not surprising that Jane Austen developed a strong scepticism about contemporary ideas of what novels should seek to achieve.