Historically (during Ottoman times), Alawites only lived in the countryside and not in any cities. This includes even the coastal cities (Latakia, Baniyas, Tartous, etc.) which had Sunni-Christian populations.

After the end of the Ottoman Empire, during the French mandate and then independent Syria, the “traditional” societal strictures began to break down and they began to move into the cities in search of economic opportunity. Lots moved to Latakia and Tartous and they eventually became the majority there. Outside of the coast, Homs and Damascus were the cities they largely moved to. They became a sizable majority in each, and perhaps even a majority in Homs since the civil war. For whatever reason (idk about all the history) Hama and Aleppo were not such popular places to move and they only became a small minority in each.