If you're a builder manager you can make more, but if you look at residential housing, the people at the bottom aren't making shit. Mostly it is a poorly regulated, non-unionized, highly dependent on under the table pay industry.
But anyway about it, if there is suddenly an influx of manual/physical labor poured into the market, labor prices will drop far below the living cost and all hell will eventually break loose.
I'm not saying it's correct or fair that a trader sat at his desk can contribute £20 million to a country's "output", while a builder, working his backside off could maybe add £100k, but that's the world we live in...