Singapore needs for foreigners, because locals are leaving in droves. The cream of the crop - those spoilt ungrateful brats - have moved to the west for more opportunities. So we need foreigners in top corporate positions.
As for the bottom rung, how many sinkees want to become maids and cleaners?
For those companies where foreigners directly replace locals, don't blame my masters. Blame the companies who capitalise on this opportunity to hire cheap foreigners. If they hire the wrong people, they will be the ones suffering for it.