Will mining in the (far) future produce a payout? According to this question, there will only be 21 million bitcoins at most. These coins are being produced logarithmically by mining, so the payout will decrease as time goes by.

When all 21 million bitcoins are in circulation, will there be any reason for mining? Is mining only useful for us "early adopters" or will it be a permanent part of Bitcoin?
Miners earning = block reward + fees

Miners will continue to get block reward in the next hundred years, but long before the reward "stops", the miners will get most of their earnings from transaction fees, so they will continue to have economic incentive to mine, when the block reward stops.