[...] Since the masternode reward will continue to climb monthly until 60%, it's only going to get worse if these new coins continue to roll into new masternodes getting compounded. For instance, at 580 masternodes currently, the entity is generating ~286 coins a day (0.494/Dash per node daily)... that means over the course of just one month, that entity can bring online another 8 masternodes (and that's just today's figures which doesn't factor in increasing rewards and compounding from new nodes). It's not hard to see how over many months that the entity will continue to increase it's coin supply ownership and composition of total masternodes.
Percentage wise it stays the same (580/(# of Masternodes) * 100) because others also get rewards and create new Masternodes.