Remember, sir, that Leto has his Tomb of the Skull, Paul is revered as a liing god, and Leto the Second is the God Emperor of Dune.
Mock not the Atreides.
Seriously though, there were associated cult shrines throughout what had been Achaean Greece and Crete. Simply because Atreus only had a dedicated shrine at Mykenae doesn't mean that he wouldn't receive associate worship at the temple of Menelaus and Helen outside Sparta, for example. I would be amazed if he didn't.
The present generalisation and simplification of cults does history, and players, no favours.