Pompeii is one of the richest sources of information from the Roman world, or even the ancient world in general. It is really difficult to exaggerate how important it is in terms of information regarding topics as diverse as domestic architecture, interior decoration, art, diet, local politics, craft production, social life, civic infrastructure, colonization, religion, funerary practices--you get the idea. Pompeii )and the surrounding cities) are not, as the normal idea goes, perfectly preserved or frozen in time: the city was already in decline after a major earthquake struck a decade before, many people had evacuated meaning there are not as many small, portable goods as we might want, and looting went on in the centuries afterwards. Nor is anything in there truly unique: there are wall paintings, graffiti, and wood work surviving from other sites. But no where else has so much that is so well preserved, and nowhere else has such a diverse assemblage of surviving material.

To give one example, any book on ancient art history will mention the Four Pompeian Styles, which is the way of describing Roman wall painting. The fourth and last style goes up to 79 CE--obviously, the Roman empire continued for some time after and there is no reason to think that across the empire fashions and artistic trends stopped changing, but without a comparable site there is no way to provide a systematic description of them.

There is one thing worth noting about your premise, though: excavations in the Vesuvian cities began in the early eighteenth century and continue to this day. Only about half of the city of Pompeii has been excavated at this point, and the last time major work was done within the walls was in the 1970s.

I would recommend Mary Beard's Fires of Vesuvius, it is extremely readable, meant for a general audience, and does a fantastic job summarizing research from Pompeii on daily life.