Couldn't you design a system that monitors the amount of active currency in recent circulation and only generates more to account for that?

Then you just need low level stuff that high level characters don't have time to grind because they can get better value elsewhere. Gold would circulate to the noobs. 

 Yes. You're describing controlling the economy. Which is what I said. 

 But if you could codify it into an unchanging algorithm, it would be similar to BTC's difficulty adjustment, and wouldn't count as actively managing the econ?