I think it is a cultural thing not to look at the history; A cultural think to look for posts when they are really really fresh.

It's funny, I was just having this discussion with @bleepcoin and he basically said what you're saying.

My answer to him was that the culture on Steemit is directed by the incentives given. So if we started an Easter egg scheme to incentivise the curation of old posts, then the culture would change.

There are many short stories and funny posts on Steemit that are quite timeless, I envisage these are the sort of posts that will really benefit from a scheme like this.

Steemians starting to copy old posts, to give it renewed attention, but in the end that is polluting the blockchain

This is a good point, and the fact is having lots of duplicate content on the site devalues it in the eyes of Google, which will bring down Steemit's rankings. This is why there is such a focus on new and original content. So that is an unforeseen benefit of a scheme like this.

Thanks for your comments :-)

Cg