I think a lot of games are made open world because it feels more massive. I don't mind games being open world or linear, it's a matter of getting their design right and making the worlds believable and interesting. Ubisoft's open world games have completely lost that touch for me (Assassin's Creed, Far Cry), as neither their story lines nor the worlds are very interesting to roam around in anymore.
I loved open world games where the play area would still be somewhat focused, and over the course of the game the player has a significant effect on the world. Outcast and Grand Theft Auto for instance feature worlds that become less or more dangerous, depending on your actions. But in many other games, including GTA5, your actions mostly result in loot and/or buildings, but not changes to the world as a whole.