For the purpose of this discussion I think we do need to divide union memberships into two groups...those that are public sector workers and those of the private sector.

When you say that it is the boss' fault when he agrees to give you an unaffordable raise (something that I agree with by the way) we actually do have to pay attention to the man behind the curtain.  There are multiple factors in play here.

In a private sector situation, the company itself has to shoulder the responsibility to meet obligations agreed to by its management.  In a free marketplace the company that agrees to too many boneheaded contracts goes belly up when its products become too expensive to attract consumers. If only we lived in a free market society.

But in our current fascist model, insolvent companies that agree to tow the line on favored political outcomes can be bailed out by taxpayers who largely can not afford to buy the products outright.  (And if we are really lucky, like with the auto bailouts, secured creditors are dismissed so that union members are able to salvage the pensions gained by the same tactics that helped to force their employer into insolvency.)

It is through this miracle of fascism that we get taxpayer funded $7500 Volt rebates!  Sure, no average taxpayer can afford to buy one even with the incentive, but when you collect enough nickels from those average taxpayers they can be heaped together to incentivize a well-to-do-consumer into purchasing one.  The company stays afloat, the workers keep their jobs, socially conscious progressives can feel good about driving an expensive death trap, government can appease its greatest benefactors, and the only person that gets screwed is the taxpayer.  Ah, life in America.

But management, as you pointed out, is not beyond culpability.  They are afterall the idiots that signed the unrealistic contracts.  

Yet, in a state like Michigan where laws are penned in order to favor benevolent unions over disadvantaged companies, what is a company realistically supposed to do when labor has the ability to shut down a company cold regardless of how ridiculous the demand?  These corporations have billions of dollars of plants and property and other assets that they must pay for even if their company is producing no product.  They bleed money every time there is a short stoppage on the assembly line let alone ones that can last for weeks or months.  This is something that the union counts on and they have taken every advantage.  It is their most favored and least becoming leverage.  

Given this pressure, perhaps these companies should have closed up decades ago as contracts became more and more weighted toward the absurd, but a boarded-up company does no good for either management or stockholders.  If a contract demand is that a hundred or so UAW members get to sit in breakrooms and fill out crossword puzzles eight hours a day for the duration of the contract, that is a small price for management to pay if it gets a few more high quality Chevy Vegas to roll off the end of the assembly line.  So what if the next year's models cost a couple hundred more each--the consumer will cough it up.  It ain't like the consumer didn't already get screwed even with the concept of the Vega.  

The public sector unions are a problem unto themselves and are even more maddening.  

I remember the film clip of buffoon John Corzine as a candidate for governor in New Jersey speaking before his union supporters at a campaign stop.  He promised his most valuable constituency that he would help them get everything they wanted.  Similar speeches have been made by countless bureaucrat wannabees in this state.  

And yet, who represents the taxpayers if the politicians are beholden to the public sector unions?  Sure, the local school board can adopt salary guidelines for their own districts and award an additional day off or two during the school year, but it is the state level politicians that bankrupt states with unrealistic pension and retirement guidelines.  Remember, the Wisconsin referendums on collective bargaining had nothing to do with salaries but only with benefits.  Who represents the taxpayers and parents if politicians have already promised that unions will be rewarded for their votes?  (If we need a more contemporary example of this, Joanne Watson provides the quintessential--that would be the "we voted for you, now send us some money" example.)  

Can we really blame the goverment boss for giving away the store when the only reason he became the boss is because he promised to give away the store?  Perhaps not, but the rules have to change before the store goes up in flames.  Sooner or later the tide has to turn and I believe that r-t-w legislation is the beginning of a necessary tidal shift.  

It is true that I tend to blame the unions. I have worked in management most of my life and that explains my angle of observation.  Yet, does it really matter whose fault it is that we have reached this place--regardless, we must find our way out.