Part of the reason Steem is mooning is market psychology. The price languished at around $1 for so long people began to accept that $1 was 'the price of Steem' (and the Steem Dollar). For the past month the price has broken this trend. Now people who previously wrote an article, waited a week, got paid and cashed it out are now waiting. Why sell at $x when it might be $2x this time next week? This wait and see approach is drying up the available Steem in the market and pushing the price up. Those who sold 2 months ago must be kicking themselves.