Problem of understanding
Who actually runs steemit and who is responsible for the blockchains functionality? I think the witness business is hard to understand for non techs.
I guess huge investors still like to talk face to face to the entrepreneurs and like to make business through contracts and shake hands. Those are not the speculators.
Age
This tech scene is - it seems - predominantly dominated by young people and the more conservative age groups from 40+ - who already have money in their regular accounts and could afford it - are doing something different than speculating on this market. They will probably enter when the ups and downs are no longer so unstable, the price fluctuations are no longer so large and the whole thing can be regarded as a long-term investment - the Steem has become more established as a crypto currency to be taken seriously.
competitors
At the moment it still seems completely unclear whether Steemit will survive or whether there will be other competitors on the market that appear more attractive or trigger the next hype.
legislation & anonymity & tax
Another reason is the uncertainty as to whether the legislator will not regulate the market in a disruptive manner. I think that the issue of anonymity is an inhibiting effect here and the insecurity about legislative measures may perhaps have a deterrent effect on such mentalities. The cool heads, who don't care so much about the image of the platform and who don't care whether Steemit looks clean, are certainly already here. But people who want to do legal business and don't want any problems with the officials may just wait. The European Parliament, which has now addressed this issue, examined a total of 10 crypto currencies in a study. Steem was not mentioned there.
The legislator wants to influence the fact that anonymity is to be undermined in the settlement of currency transactions and that the operators give in. How many financially strong users will then jump out -because of losing anonymity - is unclear.