Imagine if every drug researcher in the world was working together instead of against each other.
Yes, this would be great, but not a reasonable expectation given human nature. We are all selfish, and therefore collaboration for the "common good" might happen from time to time, but it'll never be the norm while human nature is what it is. People work fine as long as they can see a direct benefit, and sometimes they’ll even do it for an indirect one, but few people will take an obvious sacrifice so that people they’ve never met will profit. Sure you can argue that life would be better overall in the long run for everyone, but we are a people of immediacy and not many can make those kinds of sacrifices. I believe it will take a complete re-wiring of human nature before anything like communism could ever work.
Take for example the effects of them winning the browser war. Their OS still lacks features others have had for ages now, and their inability to secure their products are costing companies millions in lost time and data.
I don't think anyone argues that capitalism produces the most effective result (ok some do, but not most), only that it produces a better one than anything else can. I’ll have to agree with Brad about Linux. As cool as it is, it’s no good for the public. Just ask my wife. She’s an average user who can generally figure stuff out on computers. Sure she’s had windows for the last ten years, but she’s no slouch at picking stuff up. Still, she gets massively frustrated with my machine whenever she has to use it because some of the stuff doesn’t “just work”. Linux is certainly better at some things than windows, but I’d hardly consider it an example of communism overcoming capitalism.

On top of this, Linux isn’t truly an example of communism anyway. If it were, you’d have someone managing all of the resources being poured into it so that efforts were not duplicated. You can’t tell me that the same problems haven’t been solved multiple ways in Linux and some have been found to be better than others. In pure communism resources are managed perfectly so that everyone produces what is necessary and best for the common good and efforts are not redundant.

The bottom line is that capitalism is inefficient because resources are duplicated and the best solutions aren’t always reached; however, communism doesn’t work because it is against human nature, at least on the large scale, and impossible to implement without perfect knowledge if everyone’s abilities and needs. The best we can do for now is a hybrid of the two (which is what we have in the U.S.) where we try to leverage the strengths of both systems. Better than all of this would be to change human nature, but that takes us into a whole different realm of discussion!
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-Jeff
Rome did not create a great empire by having meetings; they did it by killing all those who opposed them.