Proportionally each account forge with the same rate. No matter how coins it has.
But with PoS the rich do not get richer. No matter how much coin do you have, any one coin will always earn the same return. This is the most fair system you can ask for.
Come on it's math. Big stakes do accumulate way faster and therefore rich do get richer.
I guess I'm trying to say we have to see this reward as an average future Finnish user will see it. There is the great potential if it will be widely adopted. So as a citizen you get 100 FIMK a month for starters. That is peanuts but that is what they will have. So you have received 600 in half a year and you're thinking: should I investigate this further and maybe try forging. Hey there is these regular rewards every week! Hmmm, maybe I'll give it a shot. So rather have a rewards more often and pay them reduced whenever the forging account is a big one (saving the capital for future rewards) rather than pay a full reward twice a year.
