The simple answer is: it's not being done for the purpose of transfering real assets, it's (largely) being done for the purpose of transfering *risk* ...
Of course, the more complex answer is, well, more complex.
The counter-question is: why would you think that it would be for the purpose of transfering real assets?
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I've been meaning to mention in response to Doug's earlier comment to the effect of "sales tax is hunky dory but a tax on financial transactions is a big no-no" that while a typical worker's turnover is about 100%, a trader's is many times if not hundreds of times that. so it's easy to see that you could eat away a significant amount of principal by taxing even a small fraction of a percent.
Say this tax was 1/10 of 1%; have a 1,000% turnover rate? Lose 1%. Have 10,000% turnover? Lose 10%. Have 100,000% turnover? Lose it all. How long does it take to have a 100,000% turnover rate? I bet that many baby boomers have done so already in their lifetime in their 401ks.
The problem, of course, is scale: having a higher turnover rate doesn't correlate at all with ability to pay a tax, or appropriateness of a tax target at all. In fact, the more you have under management, the _harder_ it is to turnover everything on a regular basis. So it's unlikely this would be a progressive tax at all. The little guy will get squeezed more than the big guy.
This doesn't even take into account leverage; is 10 option contracts on a $100 stock a $1,000 trade or a $100,000 trade? Does it matter if you exercise? Calculate the tax.
Pencils down.
/jordan