The original payment system meant that posts could keep earning for a month, but that was reduced to a week for some reason. I wish they could earn indefinitely, but that may put too much processing load on the witnesses. It's not ideal, but better than nothing. This is why I put something in my footer about rewarding a recent post if the one you are reading is old.
I'm enjoying the community here and the money is a nice bonus. For now it's not changing my life, but who know where we will be in a year or two...
I suppose I was thinking more a tiered system, retaining both incentive with higher payouts on new blogs, and a value, albeit lower for interest in older blogs. Anyway, my experience of these things suggests that if the platform survives, it will find its own style and direction. We shall see :)
It's all a big experiment. We may see more changes in the next hardfork, whenever that is. The communities feature may help the smaller players. There's more the big guys could do to help nurture talent.