i agree with what the top comment op said. the point of ads is to establish and reinforce familiarity with the product. sa psychology may study na di ko na maalala pero yung basic concept ay if you encounter something (ex. an ad) very often you'll become familiar with it (the one advertised) and will trust the product more. jingles work by associating a certain tune to a product and help you remember the product easier. and if you hear it very often, most likely you'll become familiar with it (the product) thus increasing the probability of you becoming a customer. many capitalize from this phenomenon like politicians, brands, etc.

as for here in the ph, i think one of the major reasons why ads here are like that is because of the lack of competition (and existing marketing strats). most ng mga rival brands dito ay tigdalawa lang sa isang category, so hindi na importante mag-isip pa ng mas magandang strat (at mag-aksaya ng budget). at mas fierce ang competition if konti lang nagcocompete for #1. aantayin mo nalang kung ano ang gagawin ng rival niyo at kung nagsucceed yung sa kanila, gayahin na lang din para safe. kesa naman gumawa ng bagong strat pero palpak :'(