Some may argue why the superblock range is very tight and quite difficult to obtain, but the max coins are just 111 million, so the superblock has to be rare.
How do you get to the total of 111 million coins? 72 initial reward, block halving every 524160, means max 75.5 million; add in some bonus coins for the first two days, and random superblocks, still doesn't get more than 78 million?
Yes, after around 6 years, including bonus rewards and frequency of superblocks, number of coins would be around 82million. But, in mathematics, you keep dividing a number but you will never reach zero. Block halving will stop after about 6 years. Minimum block reward will be 0.017 after that. So, eventually all 111 million coins will be mined, but would take a very long time.
This is done because, i predict ASICS will take over completely in the future. Like how CPU mining became useless now, GPU mining may become useless in the years to come. With this coin supporting ASICS also, it is necessary for it to not get over soon. Who knows how much hashing power we could get in about 8 years time? It could be unimaginable and low block rewards wouldn't matter.
We wanted the coin to be future proof and run for a long time keeping all these points in mind. It could also increase the value of the coin in the later years. On an average it could take around 25 years to mine all the coins. It wouldn't be too difficult to find the block then since the difficulty will retarget every block.
Also, bitcoin is predicted to reach its 21 million mark in 2040. That's 30 years since launch.