Upcoming Terminal 4: Is There A Need?

Singapore has done it again! Just after opening Terminal 3 this year which costed millions of dollars to build, plans are underway to build Terminal 4. Amazing! What's next? Terminal 5/6/7/8/9/10?
My own opinion is that they should let Changi Airport remain with the existing 3 Terminals for a few more years, surely there won't be a 100% reduction in passengers if there isn't a 4th Terminal?
The Government's take is that with the increasing competition from China, Dubai etc, a 4th Terminal is needed to secure Singapore's position as an international travel hub. My take: Not neccessary at all. Why? All along when we had only Terminals 1 & 2, was there a big reduction in passengers? No. Then along came Terminal 3, looks pretty lifeless to me.