Or alternatively you could say writing assembler is the software equivalent of building physical things by putting together individual molecules. Physical builders work at a higher level of abstraction too.
I think the analogy is becoming a little stretched though.
In the plumbing example in the article, the plumber isn't first making pipes from raw materials. They get them pre built in standardized lengths, diameters, thicknesses and materials. Same can be said for the compiler providing a standard, generally agreed upon abstraction.
Wow, the pipe-building factory (generating standardized parts to be assembled by the plumber) to compiler building (generating standardized machine code to be assembled by the high level language programmer) comparison is really cool!
I feel like the ISO/ANSI etc standards-making bodies are where the analogy breaks into time and space.
I think the analogy is becoming a little stretched though.