Maybe I exaggerated the line workers pay a bit, but you neglected to mention what value that 'solid benefit package' might have. How much do you think that FULL health insurance coverage for the employee and his family (not just while you work there, but until you die), a substantial retirement pension, and a JOB BANK that allows you to get 90% of your pay while you sit at home. If you take just health insurance into consideration, let's say it costs $1000/month for coverage for employee/family, that seems to be $12000 a year. On an average 2000 hour year, that converts to $6 an hour for just health insurance. Seems to me that the 'solid benefit package' is a little more than an unmentioned benefit.
My FATHER has worked in a food manufacturing plant as a line supervisor for 25+ years, walking everyday on that same concrete floor you speak of. He worked those same 12 hour days and missed alot of my games, etc, so I agree it's no life. But today, after 25+ years on his job, he makes $55k a year. He doesn't get full health coverage, although the company pays a large percentage of his insurance. His retirement is in the form of a company 401k in which he contributes a percentage of his weekly pay and the company adds a couple of percent match. He doesn't complain or begrudge those who make more than he does, as he has only a high school degree, in fact he feels fortunate to have worked for a company who has given him a stable job and income.
I'm not saying that union workers don't work hard. I'm not saying to fire them all, and hire replacements at half the cost. I'm simply saying that auto workers have NO concept of the real labor market that exists outside of the auto industry and the protection of the UAW.