Doesn't that give the devs a several week head start on everyone else?
Many people have the miners working. Mining isn't our source of profit and never will be.
Additionally, linux is a free OS. If you want to mine Siacoin, it's pretty easy to install linux. Even then, we're not sure that it will work for all card. GPU dev is tricky and we're doing our best.
We've got less than 3% of the hashrate right now.