It's easy.. When you are on an exchange and have money in STEEM and it is currently not going up, but Bitcoin IS, then what do you do perhaps? Well, sell some STEEM and get some Bitcoin, make 5% profit and then buy back into STEEM and have 5% more STEEM than what you begin with.
This process takes a little while and is currently ongoing. Pretty much all crypto's are declining at this moment because of it. Once Bitcoin starts to dip bigly, I feel like this could happen any moment now, you will see altcoins rising a day after or so (give people a while for them to figure out where to best invest their newly earned profits).
In any case, if you sell STEEM now to buy into Bitcoin I think you will end up a loser. For the moment, I'd suggest to just HODL! Or switch to another altcoin if you believe that has a better chance of gaining than STEEM.
Well, I have nothing to sell or buy lol. But if all the "little" currencies are acting the same like steem - then I feel better. If steem is going down and the others go up - then I worry.
You can track the current price swings of the top 100 currencies on this site: https://coinmarketcap.com/
As you can see most crypto's are currently reporting negative percentages except a handful of them.
Though, admittedly, the whole market has been on the upswing lately - except for a few former superstars, amongst which Steem is one. I think it's going to require some significant news, or perhaps Steemit coming out of Beta, in order for the price to significantly rise. Excitement seems to have moved on to other projects, there needs to be a reason for it to move back to Steem.
For me - the excitement was the Alexa ranking so I can get my message out to more people. I will just keep posting and doing my best :)