I would say that not every industry is the same; the automotive industry has been struggling for a while, and companies aren't turning huge profits like some other ones. I could see them needing to adjust the price of parts for them to turn any profit and maintain the slim margins they're working with as it is. On the other hand, something like clothing manufacturing is a completely different story. A pair of running shoes costs ~$4-8 to produce but are sold for $80-200, and a large portion of that money is going to sponsorships, endorsements, and profit; even doubling the labour costs would not correspond to a large change in price, and they could easily shift their other 'costs' around to maintain the pricing. This is a good indication of the fact that pay is determined by what is the lowest they can get away with paying employees, and not what a fair wage is.
The concept of what the value of work is seems to be sort of a strange concept. I've worked in manufacturing (probably 12 years ago now) where most guys made $25-30+ an hour loading parts, and considered that to be totally fair, but would say that someone working a cash register would be only worth $12 (minimum wage at the time). The nature of the work was not that much different, as they both involved you standing around and doing some basic movements with your upper body, but the pay gap was pretty substantial.
It's just a race to the bottom at this point in time, and with automation replacing a huge amount of the workforce every year, it is easy to entice desperate people into taking jobs that pay less than they really should, which drives profit. This profit is largely not driven back into the pockets of the people; it is given back to investors, upper management, or others that will likely horde the money or spend it on luxury goods that create far less jobs than having that money in the hands of the workers and/or the middle class in general.
