Well, will it? I know that tech limits (and the surprise of not knowing what Pokemon you'll encounter) have been responsible for them up until now, but do you think Nintendo will ever actually make the Pokemon visible on the overworld instead?
Of course not. Random encounters is what makes the game fun for everyone. I mean I'll admit that when you're not looking for Pokemon it can be annoying, but it's exciting to see the Pokemon you want so badly show up out of the blue. I mean how fun would it be to see a shiny Pokemon in the over world and just being like, "oh there's one now." I'm sure shiny hunters get chills from seeing a random shiny.
Random encounters is a trademark and it adds nostalgia to the game. And besides do you want to be the one to make about 300+ more models (excluding shinies) and coding to make the game seem more realistic and do it before the deadline? It just doesn't seem logical for this type of series unless you had Pokemon follow you around again.