Price of BTC has a bigger impact on Steem price than anything at this point in time.
Right, but nevertheless other altcoins, whose prices also denpend on the price of BTC, overtook STEEM, which is only ranked 60th at CoinMarketCap nowadays.
According to the stats I'm informed of: most people don't downvote.
They just don't dare to downvote, even if in future downvotes will be theoretically free. The threat of retaliation is too strong.
Look at the comments under this article for example: a whale upvoted his own comment to the top and flagged another comment which actually got way more upvotes. Even if downvoting would bring some curation rewards and even if they don't like his behavior, I doubt that people would flag the whale comment ...