That, and most individuals cannot afford an attorney. But it is true that the contingency arrangement is an excellent method of weeding out cases not worth pursuing.
While I am not claiming a perfectly analogous situation to copywriters, there are certain parallels.
The benefit of a copywriter is increasing sales. After all, who would pay a copywriter if there was not a belief that increased sales would be more than the cost?
But what if sales are not increased? Who should bear the risk?
If the buyer does not use the sales copy as-is then a fee would be justified.
But if the sales copy is used, and sales do not result, is it because of the copy or because of another problem in the sales process or because the product is crap?
In that event, why shouldn't the risk fall upon the copywriter for not properly investigating and evaluating the project before making their commitment?
I'm guessing more than copywriter will say they would be homeless if they relied on claims of commissions being paid from sales, or promises of future projects. I also deal with such promises, which are really empty, sugar-coated ways of asking for a freebie.
But at the end of the day that still goes back to the question of properly evaluating the project.
Seems to me that relying on commissions could be more profitable, while at the same time signaling to bad product owners that they have a problem.