Necessity of another costly MRT line?

Government approves $12billion MRT downtown line to be built by 2018.
I do not support this decision.

1) The viability of the Circles Line is still unknown. It seems too hasty to approve another costly MRT Line.
2) The current lines are already very dense. There are unlikely much time savings for commuters using the new line.
3) New MRT Lines likely will result in removal of many existing bus services. May affect convenience.
4) Existing Lines are not run to maximum capacity yet. Moreover Circles line are in the pipeline.

Probably
1) Regardless the lines are making profit or loss, our Million Dollar Ministers will be able to justify anyway.
2) When the lines are making a loss, our fares will just rise. Who cares anyway.
3) The projects will be given to all our Temasek Linked Companies anyway. Its the government earning back the money.
4) Our ministers don't use the MRT anyway, they don't know the frustration of changing the MRT lines and having to walk long distances up and down the stations.