You could, but imitations have no value.
BTC has value because of the network hash (unhackable) and the acceptance associated with it--it's the first.
Similarly, you can mix some sugar, molasses, and water and create your own Coca Cola, but it's not Coca Cola, it's just sweet water.
Do you believe that Steem will one day be as valuable as Bitcoin? It's my understanding that when you get Steem you then need to trade it for Bitcoin or another cryptocurrency before you can sell it for USD or another currency. Is the hope that one day you will be able to trade Steem directly for $?
I think it's possible, in the same way that steem impacts the network that was created. And helps to solve problems that can be emerge, like high costs of intermediates in user -bank -user as the blockchain comes to solve