First of all, CPG was sold to the Aussie. It is a commercial thing not a political one. If you want to see how oppo manage their wards, go to punggol east and aljunied which are transforming into kampungs. Hougang never progress much from a laid back kampung with HDB flats.
Your observation is the same as what papees por-lan-pars used to say about Potong Pasir but CST managed to remain as their MP for many years. Hougang is still in the hands of WP even if it is like a kampong.