Surely there is enough highly talented, smart people to have a crack at a political office that's been held for decades and of course an enthusiastic young generation who have lived under this system perhaps interested in a change? It's a country with one of the highest average IQ's on Earth and I'm always intrigued by the statement "no viable opposition". There's definitely a viable everything else in the nation, wondering why politics is so different. It's an amazing place to live from my Australian perspective.
I'd argue that everyone couldn't care less given the history and are fine with the system as exists. Which seems to backed up by a lot of elections.
Not all political candidates seek power, money, or status.
Some might just want parliament to be more diverse than one party making up more than two-thirds of it, and having the power to push through constitutional changes any time they want.
Aspiring politicians who join the PAP hoping to steer it from within probably haven't thought about how they're subject to the party whip [1], and how nobody has disobeyed the whip since Tan Cheng Bock.
[1] https://www.todayonline.com/singapore/explainer-what-does-wh...
[2] https://en.wikipedia.org/wiki/Tan_Cheng_Bock#Nominated_Membe...
What would you consider "actual contribution to the society"? Any chance you could give examples of some things you would like to see opposition candidates do?