It'll never happen purely because apple have next to no experience with the games market. Both Sony and Nintendo have their own developers for the majority of their exclusives and publish many games for their respective consoles, Microsoft have published games for many years and have a fat wallet to pay off developers for exclusives. Apple have none of these, they haven't published a big game in years (or ever maybe?), they don't have any games developers and while they have a rather sizable bank account it is nothing compared to the gargantuan funds Microsoft have access to and utilized in order to get their foot into the console market.
I don't see any new competitors coming into the console market for many years to come, it is highly competitive to the point where i think only Microsoft could have pulled off what they have in this and the previous 'generation' due to being the richest software company in the world (by a long way).