In a nutshell - service industry is an example of low cost business model. A low cost business suggest you pay low wages, because you can't afford pay high rates. Low wages repell new labor force.
From an 'attractivity" perspactive - forklifts and and service in particular - very inattractive industries, so new labour force would go to other industries even if they offer similar wage rates.
There are some other easons, but even those two are quite significant.....


Hope I didn't offense anybody :-)