There are many opinions as to how much is enough. The trouble is that there are too many unknown variables in Spore.
The biggest unknown is health care
Who knows what they are going to charge years from now?
Other unknowns is the cost of water & electricity. With the termination of the water deal with Malaysia, Spore will have to rely on technologies like desalination which requires lots of energy. The PAP has a track record of passing on costs plus profit to the public.
Not forgetting the other costs which the PAP will no doubt increae