if the incentives to run a mining gear don't exist -- the network becomes more prone to attacks, so bitcoin's security as it stands right now is closely related to its value, the more expensive it gets the more secured it becomes, hopefully, that will change one day when the majority of people start using and protecting bitcoin rather than just mining it for profit.
That's exactly what I was talking about in my reply.
If there is not enough inventive to mine Bitcoins, then it creates a security risk as more people could be less motivated to switch on their rigs, resulting in less hashrate and security.
The alternative is Bitcoin rises to make tx fees more expensive, enough to motivate people to actually invest in mining, but this eojmg affect the general users as transacting would be more expensive and holders would be demotivated to actually send bitcoins.