Some have, some haven't. It's mostly random noise. The day-to-day or even month-to-month fluctuations in the market caps of crypto projects are almost entirely meaningless. There is little to no information in the price action. Investors, or rather speculators, are like flocks of birds or schools of fish, mindlessly and chaotically chasing after whatever profits they think they can get.
STEEM is at about 31 cents right now. Does that mean Steem is now almost 50% less valuable than it was about a month ago? Of course not. Don't pay attention to short term price fluctuations. It's just flies buzzing. There is no information in it.
I agree short term market gyrations are not a true indicator of value, but how long is long term? Steem has fallen from top 20 all the way down to number 60.
I am not saying this means steem should be abandoned and it's dead. But I think it's fair to ask the question of its below market performance.
I think the poor long-term market performance of STEEM relative to BTC is because Steemit Inc overpromised and underdelivered for a couple of long years. It was terrible.
Steem is a project of many contradictions. It's got the most users and the most traffic. But its public image is very poor owing to how it got started and how many of the early 2016'ers were totally spoiled by the massive rewards. When they rage quit as their rewards naturally plummeted after the totally unsustainable once-in-a-lifetime type of lucky strike of a start, these spoiled children went on to badmouth Steem everywhere in the cryptosphere.
I think we saw STEEM bottoming out last Christmas, and if it's any consolation, the last bottom was a higher low than the one prior to that which was 7 cents in March 2017. At last, we have MIRA. We already have Steem-Engine powered tokens but Steemit Inc will now get to work making SMTs a reality at last. With MIRA and SMTs in place, development will be more app centric and the troubled early stages of Steem will hopefully be a distant memory fading away.