Whatever the name means in the hymns, the ritual tradition treats the Vishvadevas as recipients with a fixed place, and that is where they have actually survived. In the domestic ritual, the daily offering made from the cooked food of the household before anyone eats carries their name, and the portion set out is theirs. In the rites for the ancestors, a share is put aside for them alongside the share for the fathers, and the order of the two is prescribed.
That is a curious position for a category. The all-gods are given a helping, in a fixed order, at a specific point, out of the same pot as everybody else. If the name were purely a formula of completeness, it would be odd to serve it a portion, and this is one of the better arguments for reading them as a genuine class. It is not a decisive one, because ritual is perfectly capable of giving a formula a plate.
The practical consequence is that a name from the oldest layer of Indian religion is still in use in households that have no particular relationship with any Vedic deity by name. A domestic offering and a share at a shraddha keep the Vishvadevas current in a way that no amount of hymn recitation would. In jyotisha they take a further step and become the presiding deities of Uttara Ashadha, where a collective of all the gods is read as breadth of support, which is the natural reading of the name and not necessarily the Vedic one.