thats where you are wrong!
If you looked at the sdp results from the last ge, its was the what you called "rich" that supported sdp.
Sdp lost because the bt panjang hdb residents supported pap and numbered te rich.
Many of the so called rich voted sdp because they knew that for the sake of the country, good and credible opposition candidates were needed in parliament and not just for oppostition sake.
Good people like gay boy, dr ang yg and dr paul tham were all considered good.
The rich are not as myopic and selfish as you think. They know trouble when they see it and will take the necessary actions.
It is unfortunately the hdb type that are myopic, thinking of only upgrading issues.lifts/covered walkways/resale prices during the ge