This is a very difficult question to answer. I am assuming you are talking about the latest generation i5 CPUs. They are good CPUs that should last awhile. I have almost exclusively used i5 chips in all my builds over the past decade and each has served me well for about 3-4 years. With that said however, we have no idea what the gaming industry will do, system requirements wise, by 2019. Higher core multithreading is gaining steam in the gaming industry so the quad core non-hyperthreaded CPUs COULD present a significant bottleneck in the future.
tl dr --- Probably, settings will have to be flexible though.