let two persons, one of them being a "famous old" member, and the other one an unknown "minnow", write exactly the same article: you will see that the well known user has many votes within a very short time, whereas the unknown user has only a few votes within a long timespan. I will bet on that.

This observation is correct and it´s exactly the reason, why reward-oriented curation tries to spot content from unknown users. Trust me, try to maximize your return on curation for a while (if you can afford spending the time that this requires…) and one of the first things you will stop doing is voting on high-rep authors. As you say, the usual suspects of the trending page collect rewards so early after posting that there is simply no window of opportunity for performance oriented curators. Therefore I say, incentivizing content discovery actually counteracts on this kind of inequity that you find faulty here.