the project could offer the ability to reward content after the 7 day voting period. This stems from the idea that 20 and 30 year old movies are still viewed with great fanfare. Hence, older content still have a value. This might make it possible for one to get a recurring revenue stream from older content that was written.

This is SO important in order to attract film makers/animators/etc and I'm relieved that it's being discussed.

The answers I usually get to this concern are:

"Just make simpler content"

"Break your content into small fragments and upload it over time"

or my favorite:
"Steem will be so valuable in the future, you'll make up for the 7 day restriction in the long term"

_{...which I can sort of understand, but it's also kind of a **** you :D}

Also, competing platforms like Ono and Unn.io have perpetual votes. Gotta keep up with them with a SMT without tampering with Steem itself :)