Most of them don't, because they return to the delegations, that is the issue mostly :S if that approach were to be made, it would have to be funded initially by someone, and it would just keep going with the growth of the voting power, that is why it has never been done before. I have told that before xD and be answered that. So far is a solid argument, but i will keep trying saying that solution xD eventually, some day, it could be possible.
Well, if you take the cost of your work at a low cost and program most of it basically on your own, it would take a lot of time but at least it would make it cheaper on the dhf, and less difficult to get funded.