As in the title, what would happen if the Greeks dislodge Carthaginians from Sicily, Cyprus, Sardinia and maybe even Southern Spain? What would happen then? How would Carthage react? How would the locals of the mediterranean fare in the long term?
Well that's what happen 2 times IOTL, first with the Etruscans in the late 6th century and then Rome in the early 3rd but the idea is that the Greeks still manage to evict the Phoenicians from Sardinia and Sicily at least, so this might mean jeopardizing at least a couple of the attempts of a anti-Greek coalition, but it also doesn't mean Greeks conquering Italy, I was really focusing on the naval conflict in those colonies, not an Hellenistic-style empire.Roman-Carthaginian alliance against the Hellenic menace? Before the Punic Wars the Romans and Carthaginians actually got on pretty well, even briefly formed an alliance against Pyrrhus, and Sicily falling entirely under Greek Hegemony they will no longer have conflicting territorial claims and would have a strong mutual enemy to unite against.
The POD is that Greeks win the naval conflicts in the 6th to 4th century BCE. Also neither Greece nor Carthage were static entity between the 3rd and 6th century, you can't make sweeping comparison like that. The Sicilian wars were far from being one-sided.What is the POD? Alex goes west? It literally took the Romans decades to do this and they were more powerful than the Greeks.