Long term content creators would be those that are not in it for a quick buck. They are set to create consistent and quality content and still flounder because they do not find an audience.
Steemit's very structure and lack of discovery features promotes ethereal, daily and almost throw-away content. Its not well made to support someone writing a well researched post once or twice a week, especially about topics that aren't Steemit or Cryptocurrency.
I disagree in most of that and agree with a little.
I do not think in general that ethereal throwaway content is promoted or does very well at all.
I agree on the fact that it doesn't work the best for people who post once or twice a week. However I would say that is the same for many platforms. You have to build an audience. it is harder to do that if you just pop on and off occasionally. I think that is the same for most types of social media