I wonder how much of it is symbolism and aesthetics. When we think of the working class, we think of what you say - factory workers. We also think of rundown housing, ownership of a shabby secondhand car at best, limited schooling, etc. People who own a two-storey house by a canal on the Gold Coast with a pool and two reasonably new cars in the driveway would never call themselves working class even if they are living from pay cheque to pay cheque from secretarial, retail, or tourism jobs. They may identify with the "working families" rhetoric so popular with Australian politicians in recent years, but "we live in a good neighbourhood! We're not working class like those poor people and criminals in Ipswich!"