Mining in one years time In about one years time, when mining is really difficult, what would be the incentive for people to mine? 
And if there aren't enough miners, how would transactions succeed?
Won't happen because of pure greed, if people start leaving difficulty will drop and then it will become profitable again plus even if the normal person can't mine we will have some big company that will profit from mining and keep the network running. This poses other issues when big company's get involved but that's out of scope for this question.