I'm not normally a union guy, but I am a 'use your brain' guy, and thus I don't think you should be trying to fit reality to your preconceive notions of it but rather let evidence drive the theories.
I believe historically unions were required to fix horrible conditions and situations, but as they are successful their utility decreases more quickly than the changes they cause. Over time they become like most human institutions that put the institution itself above the individual, and cause more harm to the people they were created for than they help them.
That doesn't mean they have no purpose in modern society, just that they tend to outstay their welcome... again, like most institutions. There are probably unions out there that through the effort of individuals keep it focused on the big picture and the real (rather than nominal) welfare of its members, but I suspect those are in the minority.
I think the causes for the current WGA strike are reasonable and that the union/strike are probably the only realistic ways to get those issues addressed. The best writeup I've seen is from Kung Fu Monkey, whose blog I started to follow a few months ago for various reasons.
Since you guys are on strike, and as the joke goes you can't write new, creative picket slogans because you're on strike, I'll donate the following:
One Two Three Four Insert Witty Slogan Here
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