Coupled with some political issues of the last 3 years (mostly resentment towards lower income migrant workers from neighbouring countries), we went from "our entire service industry — and construction and retail and manufacturing and everything other than high end jobs — IS staffed by low wage workers" to "holy shit, let's not let too many of them in and only bring in the educated folks with degrees".
This has created and worsened the labour situation. Additionally, with some of the highest residential and commercial rents in the world (on par with or similar to Manhattan), it's a very big gap to fill. I have lots of friends who run F&B establishments — and it's something they're all grappling with. Retail, too. You seem to not be able to hire any Singaporeans for the love of money, of any amount. It sucks, esp since we have super exciting growth in our food/bar scene right now.