The fetish for etiquette really took off in Britain around the 1830s. A clear indication of this was the rise in printing of guidance books on the subject.

The reason for this was the increasing social mobility of merchant classes into the 'aristocracy'. Whereas in other nations such as France, the middle classes who had made money by business and the like had to overthrow aristocratic power by violence, in Britain there was a more 'accommodated' transition. This meant that the trappings o the aristocracy became a sort of blueprint for how the newly rich could take on 'culture' and act as though they had been wealthy all along.

You find this situation parodied in many great fictional works of the 19th Century, featuring broke aristocrats trying to 'keep up appearances', and on the other hand the gouache neuveau riche, often artisans or educated merchants and their children, trying to act like they were royalty.

This reflected a wider conflict in British society in the 1830s, where business classes sought to end the monopolistic and protected mercantile systems that had previously existed. Lower social classes were also demanding respect and power, and a rapidly increasing population and stagnant economy put pressure on towns and the food supply.

Sources: Eric Hobsbawm, The Age of Capital and The Age of Empire.

There's a really awesome article (book?) by Norbert Elias called "Court Society" that goes into why etiquette was so highly prized, especially in Louis XIV's court at Versailles. Versailles is as big as it is because Louis actually housed all the country aristocracy inside it - this was a big part of his centralization of the French state. When aristocratic relations go from being about land to positions of power in one big building, positions of power need a new form of articulation. Enter etiquette: through displays of their knowledge of etiquette, those in power (longest serving, closest to the king) could distinguish themselves from the newcomers and the weaker residents.

Steven Pinker actually writes about a similar topic in The Better Angels of our Nature: Why Violence has Declined.

Elaborate codes of etiquette seem to generally arise out of societies where it is not difficult to offend someone in such a way that you be asked to answer for it with your body. In many cases, whether you are talking about Europe (from the late medieval to the early modern period), feudal Japan, or the antebellum American South, you're looking at dueling cultures.

Of course, there's also the fact that these are also cultures where there is intense economic stratification, and so the social pressure is to distinguish oneself as starkly as possible from the ones beneath your social position. Trends in styles and social trappings tend to be cyclical, with the poor imitating what they see as symbols or styles of the wealthy, and the wealthy then abandoning those things in disgust.