[dcolkitt]

The problem with Bitcoin is that the current economics of the network are long-term unsustainable. The current incentive for miners to secure consensus are block rewards. But block rewards halve every four years (which is how Bitcoin enables the hardcopy of 21 million BTC).

That means that over the long-term the incentive for honest consensus tends towards zero. By 2032, the cost of 51% attacking the network for one day will be less than 0.1% of the outstanding market cap. The long-term theoretical solution is to replace block rewards with transaction fees, however because Bitcoin is not a Turing complete smart contract platform the demand for block space is essentially a rounding error.

[DickingAround]

Block rewards get replaced with fees. Part of the 'blocksize wars' was the decision to not just increase block sizes or (or course) increase issuance of bitcoin but to be honest and recognize that there will be constraints on what's in the core chain and it's going to cost money to get stuff in the core chain. There are fees now and eventually fees will replace inflation. But it's going to be hard to 51% attack it because there will be still people mining chasing those fees.