The system was designed that way for every miner to compete, not for everyone in the world have equal amount of coins...
The system wasn't "designed" with megafarms in mind. If anything, the system was "designed" to allow anyone with a CPU to participate in the network, incentivizing random_d00d to join the Bitcoin ecosystem. Megafarms broke that.
Claiming that megafarms help to secure the network borders on absurd. Concentrating so much hashpower solves a nonexistent problem, while creating a real ones: greater centralization and entities with both financial incentive and capacity to corrupt the network.
TL;DR: foxes guarding the chicken coop.
You act as if mega CPU farms wouldn't exist if ASICs didn't come around... Back with CPU farms we had botnet issues, those people are even greedier since they are using other's resources completely for their own gain.
I'm not saying that CPU megafarms are impossible, only that megafarms of any kind are undesirable.