All SHA-256 Alt Coins I can think of derive their value from what they are worth in BTC, there isn't much of a market currently for Alt Coins not tied to BTC..
Alt Coins derive their clients, etc. from the BTC client...
Another note, if you think BTC can be volatile watch some alt coins.. You can go from profitable to a loss before your coins mature so keep an eye out..
I get what you are saying but also one more thing, back a few months ago 336 MH/s used to even be profitable, now coins much more profitable than BTC , still 336 MH/s is nothing but a few cents for them as well, so I'm guessing BTC does have a thing to do with it.
Bone up on economics, law of supply and demand, results on increasing inputs. "ROI" is constantly thrown around wrong, and measuring profitability on an unknown future value is not an exact science.