Gilgamesh on 02 February 2015
I'd say 15 - 20 years.
Might see games close to 100GB by the end of this gen, already most games are hovering around 35 - 50 GB. Usually every generation is a 10 times the jump for space in a game, so next gen (eigth gen) will probably hit around 500GB for some of it's biggest games, so the gen after that (ninth gen) might hit the 1 terabyte mark around the end of that gen. If we go by the average 7 year life for a video game generation, it should be around 2027 - 2034.
