Rent-seeking
In economics and in public-choice theory, rent-seeking involves seeking to increase one's share of existing wealth without creating new wealth. wikipedia
@krnel (with a little input from me) has a good discussion of how this might apply to steemit. There's a bit of nuance in how this applies - it's not quite the same as in classic economics (I think), but it is certainly something that is putting the brakes on growth here.
Regulatory capture
Regulatory capture occurs because groups or individuals with a high-stakes interest in the outcome of policy or regulatory decisions can be expected to focus their resources and energies in attempting to gain the policy outcomes they prefer. wikipedia
I have discussed how I think this applies to steemit, but you don't need to use too much imagination to see where I'm going with this if we recognise that the top 20 witnesses are essentially making policy/regulatory decisions.
Thank you very much for this. I will review later and then again.