I am going to be addressing this simply from a profit-driven view.
It does seem that there is a "shelf life" for content (no matter what form it takes - written, audio, video, etc), and that "shelf life" is 7 days. It doesn't mean that the content stops being valid, but it DOES decrease (possibly even stop) it's value, both once the 7 days are up and technically, even before (because if it has such a short amount of time to generate profit, it would be inefficient to take the time to produce continuous, consistent high-end content). Thus, what will happen (in my opinion) the majority of time is quick "news updates", as well as simple to produce content that can be generated in a short amount of time (memes, for example), and finally - content that is driven by the very thing that "mints" the money (cryptocurrencies, Steemit, etc).

Now, this isn't to say there isn't high quality content out there, but I am saying is it's going to take a serious amount of digging to find the gems - and it's not their fault. The deck is stacked against them.

Does this make Steemit a less than optimal place to post high-value content? Not at all. It just means that it is going to take even more hard work getting people to see your work, and any profit you earn should be considered - at best - a welcome but fully unexpected surprise. At least, until you have done enough grinding to make your content to be considered "consistently high value" by the people who follow you.

For example, I fully expect and plan on 100% of my content generated on Steemit to be "worthless" from a profit-driven viewpoint, and truthfully, I'm not doing it for the money. My aim is build something (a stable, easy to interact with, high value content generating roleplaying community that uses Steemit as its social media platform) that I feel has the potential to be great. If money follows, awesome. I'll reinvest a lot of it into the above-stated goal and probably use the rest to further a personal goal of my own (published rpg setting).

Sheesh. I don't know if I addressed anything you brought up, but thanks for letting me ramble!