In terms of the Greeks, I suspect the omission has to do with Eris being potentially associated with the Athenian Eupatridae who supported the traditional landowners there. Eris was intimiately associated with the marketplace, and I have found evidence of historical worship of some kind in Attica...but not after the 6th century BC.
Most other Greeks had a very low opinion of commerce for various cultural reasons, and I suspect that had a lot to do with their dismissal.
As for the Romans, they repackaged Eris as
Bellona, based off her aspect as Enyo, the sacker of cities. Apart from that, for the Romans, Eris was just another degenerate Greek goddess. During most of the Republic period, interest in anything from Greece was generally the preserve of a small intellectual elite...apart from poets, historians and philosophers, there was nothing there of interest to anyone, for the average Roman.
Besides all that, she was a very minor goddess with a small following, which then degenerated into an entirely mythological role. Great houses and patrons would normally associate themselves with one of the more powerful and well known Gods, and artists were of course dependent on such people for their living.
