Instead, all altars and hearths were places where she was worshiped, from the cooking fire in the poorest of homes, to the communal hearths found at the heart of each city, to even the altars found in the temples of the other Theoi. ALL sacrifices and cooking were under her particular aegis and as such she was probably not being “slighted” by not having significant sanctuaries built in her honor because she was being worshiped every day in every home.
On the contrary, it was felt in the literature that I have found that Hestia was of primary importance — equal to the other Olympians if not of more importance. When Plato described his “ideal” city-state, he included Hestia as one of three specific Theoi to be in a special district at the center of the city. The other two were Zeus and Athena. THIS gives an indication of her importance despite the lack of major cultic sites — because she was literally worshiped everywhere.