The interior of Peninsular Malaysia is rich with mineral resources, and when the Chinese migrated to Malaya, they tended to congregate in the interior, rather than the coastal areas. Only the later dialects/migrants who came later ie the Hokkiens and the Hainanese would populate the coastal areas, as the rich interior were already taken by the Cantonese who came much earlier.
In Taiping, one will find a street where goldsmiths operate side by side. Goldsmithing in Malaya is parochially a Cantonese industry. That is why one will find most goldsmiths with Cantonese sounding names like Poh Kong, Poh Yik Thye etc.