The way I see it, by downloading the software, they are paying, just not with money, the same way they "pay" Google by seeing ads.  These people are offering Bitcoin (the idea) a share of their mind and their time.  They are incrementally adding to the entire Bitcoin-based economy by considering accepting Bitcoins in exchange for their goods and services.  They are paying with their willingness to change how they see a BTC as something worth 0.00 to them, to something worth over $10.  Of course, I am also respectfully keeping in mind that you have contributed substantially to bitcoind, and I have not.

That said, I am one of the few who indeed offers bounties for implementing my pet features, which nowadays usually take the form of a 10 BTC silver coin.  I have paid bounties for many of the recent improvements to bitaddress.org, and I have several open bounties for features I'd like to see, including sweepprivkey and a option (that can be enabled by a user, even if command-line only) to create and maintain a disk-based index in bitcoind that allows quickly finding all standard unspent transactions belonging to a given bitcoin address (which is what sweepprivkey would depend upon).