It's true on Steemit that most votes come early on after posting. However, that's because Steemit heavily favors recent content over older content. It is extremely difficult to find older content except by google search. And if you try to read older content by an author here, there is no way to sort the posts from older to newer. Everything is geared to see only what's recent.
The "7 days to $0" idea only compounds this -- and it means you should never post your best stuff here and only here. Especially when it becomes a permanent donation to Steemit after 7 days (stuck on the blockchain).
I believe content should be able to receive rewards beyond 7 days ... forever.
For me, the 7 day limit forced me to reconsider a project I was planning on Steemit. There are better options financially (outside Steemit) that allow for the possibility of residual income after 7 days. As far as this project goes, Steemit will be a place to recycle the project's old content to give it a second life.
I only recently learned about all this and posted 7 Days to $0: Those Worthless Old Steemit Posts.