This is how I do the math (after showing my work here I now need to change the descriptions 
):
Find the maximum amount of CGA (if diff < 3) to come into existence (not counting bonus blocks):
1 month(30days) = 2,592,000 sec
2,592,000 sec / 40 sec blocks = 64,800 blocks per month
64,800 blocks per month x .33333333 per block = 21,599.999784 CGA per month
21,599.999784 CGA per month x 12 = 259,199.997408 CGA per year
100 years (if you live to 100) x 259,199.997408 CGA per year = 25,919,999.7408 CGA in a "lifetime"
Minimum amount of time to "mine out" CGA:
10 Billion CGA / 259,199.997408 CGA per year = 38,580.2472993827 years
So, if the difficulty for CGA never goes above 3 for 38,580.2472993827 years then CGA will be mined out. But this is very unlikely, the difficulty will rise in the first few years due to technology, making CGA more scarce and theoretically more valuable.
):Find the maximum amount of CGA (if diff < 3) to come into existence (not counting bonus blocks):
1 month(30days) = 2,592,000 sec
2,592,000 sec / 40 sec blocks = 64,800 blocks per month
64,800 blocks per month x .33333333 per block = 21,599.999784 CGA per month
21,599.999784 CGA per month x 12 = 259,199.997408 CGA per year
100 years (if you live to 100) x 259,199.997408 CGA per year = 25,919,999.7408 CGA in a "lifetime"
Minimum amount of time to "mine out" CGA:
10 Billion CGA / 259,199.997408 CGA per year = 38,580.2472993827 years
So, if the difficulty for CGA never goes above 3 for 38,580.2472993827 years then CGA will be mined out. But this is very unlikely, the difficulty will rise in the first few years due to technology, making CGA more scarce and theoretically more valuable.
and what will we do?
over 15 000 years to teach extraterrestrial intelligence how to mining?
259,199.997408 CGA per year - not rare 100%
maximum of 20 000 000-30 000 000
I think that 2 000 000-3 000 000
and while I don't have 100% confidence that when you have reached the end when 20m, not even sure that when 2m
if we decide 2m for 1-2 months the rates of interest may be increased to 100-1000%
I believe that mining will become something that everyone will know how to do. It is getting easier and more "user friendly" every year. As time progresses mining is going to get more popular (especially if Bitcoin gets fully adopted world wide). So the network will grow.