Currently there is a supply of 72,998,905 Ether. This is the 60,000,000 from the IPO + 12,000,000 for foundation/development/contributor rewards + about a million from mining since Frontier got its start. Now from mining, assuming the 15 second block target holds, we get an annual inflation of 10,519,200 Ether (5760 blocks/day * 5 ether per block * 365.25). So only if Ether mining continued for 7 years would mining rewards surpass its premine. But then there's this, scroll down to Difficulty adjustment scheme: https://blog.ethereum.org/2015/08/04/ethereum-protocol-update-1/

At Ethereum block 200,000 (under 9 hours away as of writing) the difficulty starts to increase little by little beyond the nethashrate's target. This scheme is to freeze out the network to allow it to switch to proof-of-stake. I haven't read if block target or reward will change at the PoS changeover, but if it stays the same it will still take just under 7 years for the Ethereum network's mining/staking rewards to match the 72 million Ether premine.

I think for this reason a healthy fork of Ethereum such as (maybe) Shift will make a healthier ecosystem for this type of network. It's a good selling point for Shift too.