A resounding YES.
The reasons are logistical, all casting agencies and ad agencies are in Manila. All the industry people are here. There maybe some gigs in the provinces, but most likely these are not big accounts.
If you're living in the island-type provinces (Palawan, Romblon, Iloilo, Cebu) and you're seriously considering an entertainment career consider moving to Manila. Give it a year of endless casting calls to finally see some results. Things don't happen overnight unless you're that lucky bastard with that exceptional talent or beauty. Those living in Luzon are quite lucky. There are talents as far as Ilocos, Baguio and Quezon province who would commute and endure long bus rides just to go to casting calls.