What Riverhead said.. A sharedrop is not pay for the software, it is a gesture of goodwill towards our community. Gestures of goodwill cannot be understood if you think in terms of pure cost/benefit. If a friend helps you move a couch you don't pay him in cold cash as that would offend and reduce him to a worker.. you treat him to dinner and keep an unspoken promise to help him out in the future.
Demanding gestures of goodwill makes them impossible.