Everyone who came to decry the idea of protocol level inflation is failing to understand is that a cryptocurrency network only exists due to miners. If miners stop mining (due to the block reward getting too small and transaction fees not keeping up), the network rapidly loses strength (leading to loss of value). The problem with this collapse is it compounds on itself as less valuable tokens translate to even less incentive for mining.
Sorry, I don't understand. Why do miners matter to the currency value? If they all stop mining, why should it have an adverse effect on the bitcoins in existence?
Well in the extreme, if they stop mining no TXs can go through and so the currency is worthless.
One also has to bear in mind that the security of a transaction against double spending is defined by the difficulty to control hashpower, which is to first order the real cost of the total block reward. If the total block reward, fees and all, is just a few millies.. then you know you shouldn't trust much more than a few millies in a single confirmed TX with untrusted parties.
This is all an elaborate way of saying that both these statements are true: A) I'm not going to mine the coin if it's worthless B) If miners aren't trying hard to mine it I'm not going to value it highly.