So in a year or two when the returns of mining bitcoin reach zero, what's going keep bitcoin alive when there is absolutely no [monetary] incentive to compute the hashes? I'm sure the guy who made bitcoin has some fail safe in mind?
The returns won't reach zero for decades. Not only are there transaction fees for the miners, the block reward will remain at
BTC25 per block for about the next four years.
If mining becomes unprofitable, miners will invariably drop out and the market will adjust accordingly. Capitalism's really neat like that.