Um. It's not (note the term "hypothetical"). The site has only been up a couple of months, and who knows if it as well as my projects will be that successful in it. Gittip is paying for my hosting completely however, and it took only a few weeks of the site's existence to do so. The PayPal link couldn't do that in 6 years, and PayPal donations still leave you more beholden than gittip since they aren't anonymous.

Your whole take on this is very odd as it's not clear what exactly you are expecting from gittip or why you care.