The govt's choice mah. I remember back in the '70's, in
the days of black-and-white bulky TV sets, Hong Kong drama series
were shown in the original Cantonese language. So
shiok.
And then, LKY decided to 'force' Chinese Singaporeans to learn
Chinese, and in typical non-negotiable style, no more dialects were
allowed to air on TV. Only Redifusion had dialect
channels. I remember many a lazy afternoon spent dozing off
in the hot sun as the Redifusion radio broadcast in Hokkien /
Teochew : Dai Keh Ohk Hua Ger (Everyone Learn Mandarin).

Darnit... makes me feel like some relic now! 
only left 958 broadcasting news in dialect
ok la... one compromise, Friday morning Ch 8 does broadcast
dialect operas...