Unions - Modern Ball and Chain

As I was reading about the happenings in Wisconsin, I started thinking about the role unions play in our current day economy as well as our society. The more I thought about it, more unconvinced I was about their role. And as if on cue,  I came across this excellent article which clarified my perspective. You could be a conservative or a liberal but there is no questioning the points the author makes.

I come from the technology industry which prides itself for being nimble, highly productive, highly customer oriented and highly profitable. In spite of technology being a necessity for any industry, it also is highly volatile with technologies becoming obsolete in a matter of months instead of years.
In the face of such volatility, technology industry has managed to produce stellar returns and generates a lot of wealth for employees. Defies logic doesn't it? Conventional wisdom would suggest that employees in this sector would be the most paranoid and insecure group, with rapid technology changes making it difficult to settle down and them looking for safe havens. Clearly that is not the case...

So there has to be a better explanation for the relative success of the technology industry, employees having excellent careers, making a lot of money without having any collective bargaining agreements in place. The explanation is simple and is the cornerstone of sound capitalism called "Competition".

As a hiring manager, I am constantly looking for ways to convince skilled potential employees to join us. More often than not, the right person can negotiate their pay package and benefits irrespective of the state of the economy. This works the other way around too i.e. if there are more skilled candidates than positions, the lower their negotiation powers. The beautiful concept of supply and demand.

So why do NBA players who make a whole lot of money than software programmers need a union? Why are teachers not ready to be evaluated based on their performance? Why can't public sector employees be laid off like their private counterparts?

In this day and age, where the supply and demand information of skills are available (with salary surveys) why should anybody need unions to negotiate on their behalf. If  an employee is good, why can't he/she demand a raise or threaten to leave to join another well paying job, or conversely if she/he is bad, why do they deserve a high paying job?

Alas, this does not make sense at all. :-/