The maximum number of coins is also irrelevant (aside from technical reasons), particularly as mining output scales linearily with the amount of the initial stake. Does it matter if bitcoin has 21,000,000 or 21,000,000,000 coins, if everything is scaled up similarily?
this. Mining output is 0.5x (x = number of ethers bought initially) per year. Linear inflation.
There's no cap, so where is the 1.2 trillion coming from? I think it's probably based on some assumptions (mainly a certain "x" and a certain percentage of coin loss?)