Siacoin currently has a circulating supply of 27.67B coins. It is worth noting that with a current coin price just under 1 cent, there isn’t a lot of room for this coin to grow. A move to $10 would give the company a valuation of over $28B, which just isn’t feasible (as it would give them a market cap nearly the size of Bitcoin). A more reasonable long-term target would be $1, which is still more than a hundred-fold increase.

You screwed up your calculations there a bit ;)
SC is now ~0,1 cent, a $1 valuation would already mean a almost BTC-like market cap.