Steem dollars are available for trade straight to BTC on Poloniex.

the company is the coin but it is also the platform and community we are building around it, Will it be around in 2 years? if it is reddit will be a ghost town by then and steemit will have been the first true success at getting cryptos into the hands of the masses as well as the first "replacement site" the next replacement will hopefully be for facebook (I've heard AMP Synereo could be it)

and if that is true... then how much will each STEEM be worth at that time? 20.$? 100.$

You are 100% correct tho it's not quite as good as it first sounds to a new onlooker.