Every crypto coin's inflation curve has been designed to not merely reward mining, but to reward mining early
. This combined with the lottery-style reward means that if the exchange value of the currency does not go up, the incentive to contribute to the network goes down over time.
I posit that if the network is successful, this pattern is not necessary to make the investment lucrative for early adopters. It necessarily creates a "peak coin" situation where the production of currency units is never going to be as efficient or productive as it was the day before. Specialization of miners is unavoidable, but we still want to see an incentive for small contributors to the network.
Now, I know the exact quantity in circulation is not a big deal, but my concern is about incentives. In the world of gold mining or oil drilling, yes, there is a finite amount that will be extracted and as time goes on this gets more difficult. However, within that pattern there are booms of production. Certain participants in that industry sometimes pull off a hugely productive project. So the production rate over time is not a straight, asymptotic thing. Sometimes it rises, sometimes it falls, but in general it gets more difficult all the time.
If the block reward adjusted based at least partially on the size of the network, then more participation in the network would create more currency. Having a growing number of participants struggle for shares of a fixed-size pie seems to me like it will make helping the network less remunerative the more people are doing it.
It would be nice to see a system that rewards people for contributing useful compute cycles and disk space to the network, no matter how small, instead of creating an arms race to win a lottery as in bitcoin.
Maybe all I've done here is outline an idea for my own sub-coin