And I think this is a reasonable choice, primarily because you've made a choice (as opposed to many business owners I work with who are at effect of their circumstances).
Colin, I don't think I've had a chance to acknowledge you for supporting / allowing Patrick to write up the article I linked above. That was a brave call, and few business owners are bold enough to stand up while someone calls their baby ugly. (I think it was a masterpiece article on his behalf, and that Thomas makes a good point in his response here too AND I support your ongoing choices. I'm on the record as a long-standing fan of the picodollar.)
Tarsnap is, at least on HN, a great case study in the pricing and product choices startups have. I would make different choices regarding pricing (hence my grandparent post), but I would never have the capability to create a product remotely comparable - and the product is more important.