KEgstedt: I think calling a sale "Piracy Amnesty" in order to call attention to a substantial problem for indie developers is fair game (pun not quite intended). While previous pricing strategies may well have contributed to more people choosing to pirate the game, I'm really worried about the "suit yourself, developer" mentality represented by some posters on this thread. There's a fine line indeed between that kind of spiteful, begrudging comments and actively legitimizing piracy.
Irrespective of pricing (and we all know about the "race to the bottom" in terms of iPhone games and what *that* means for indie developer sustainability), you'd be hard-pressed to find an indie developer who would agree with the idea that a game such as Machinarium which took a considerably amount of time to create can be initially sold at anything less than $20 and still make financial sense for the developer in question or the industry as a whole. Good, well-produced indie games must be able to cost more than $5-10 without provoking a "they deserve all the pirates they can get" response from the PC gaming audience. Otherwise PC gaming truly deserves to be dead.
I see why you're saying what you are, really I do. You love gaming and want gaming to thrive (not just big game publishers).
However, it's just not reality to think gaming is somehow immune to the laws of economics. Price influences demand. Whether devs think developing a game is "worth it" or not at a certain price point is, frankly, immaterial. Economics doesn't care.
Also, reflecting on piracy rate or unit price solely is somewhat naive. Neither tell the full story, 99% piracy doesn't mean a game failure if you still profited millions off the 1% for which you were paid. A 1 dollar unit price is more valuable with 1000 sales than a 100 dollar unit price with 5 sales.
Don't let a single statistic "lie" to you, because something like "90% piracy rate" doesn't mean anything but "for every person who obtained a copy by paying for this item, 9 obtained a copy by not paying". It certainly says nothing on its own about profitability.