Linearity is really present in all games. I think what a lot of people get confused with linearity is when the game is essentially one long corridor, after you do one thing, you move straight onto the other, with no choice about where you go in between.
Devil May Cry is a classic example of that. But I don't consider that a bad thing, I love DMC (I own but have yet to play the sequels so that may change). In a game like that, that amount of linearity is necessary. I mean you're in a castle full of monsters, all of which want you dead and if you don't sort this shit out Mundus is going to rise again and take over the world. So, what are you hoping to do in between kicking the shit out of hellish freaks? Although many people dislike this sort of game, essentially DMC is a "go and a get a key, killing stuff on the way, open the door, go find the next key, kill some more stuff" kinda game. I don't really have a problem with it. I don't see how free-roaming could be incorporated into a game like that and I wouldn't want it to be. (See also Max Payne, Abe's Odysee/Exodus, Most FPS campaigns and Prince of Persia Series)
Then the step up from that is games like Ratchet and Clank, Spyro the Dragon, Super Mario 64, etc. Where there is a clear path, but you do things in what order you like, within reason. In those sorts of games theres no sort of illusion that there is a final goal and you often have a good idea what that is. There is also a path you follow but you're often presented with something like 5 things you have to do and you do those 5 in whatever order you like, and so on. Theres also often optional things to do which aren't necessary to advance with the storyline, but completely them gives you a nice item (like all the extra stuff in R&C) or it is required for 100% completition (note how you can defeat the final boss in spyro without 100%).
Finally there are games which are still linear but because they include free-roaming people think they aren't. Examples which spring to mind are FFXII and Black and White. In both of these you can spend as much time as you like messing around doing whatever you want whether it be side-quests or just wandering aimlessly. It often pays to do both of these but eventually you'll get bored of wandering around like an idiot and get on with the story. Note that although both the above mentioned games let you do things in your own time, they both have a very clear storyline which can't be altered, no matter how much you spend wandering around like a lost drunk, eventually you have to get on with it, even if only to give you wandering pastures anew.
I would say the games which have provoked this anti-linearity are not much different from this. Although I haven't played the GTA series much from what I can see there is some sort of story to them, although the main appeal seems to be that you can wander around doing whatever the hell you like and blowing shit up, there are missions to be done, and eventually you'll have done all of them and the game will be complete, whether the game ends here or whether you're simply allowed to get back to the important business of blowing shit up I don't know. But the fact remains that even GTA has an element of linearity in it.
When it comes down it, every game is linear whether it be a clear story of just a final goal. Hell even AoE and Civilization are linear, eventually you want to wipe everyone out or wipe everyone but your allies out and then you've won. Without that the game has no purpose, and in that aspect it is indeed linear.
Devil May Cry is a classic example of that. But I don't consider that a bad thing, I love DMC (I own but have yet to play the sequels so that may change). In a game like that, that amount of linearity is necessary. I mean you're in a castle full of monsters, all of which want you dead and if you don't sort this shit out Mundus is going to rise again and take over the world. So, what are you hoping to do in between kicking the shit out of hellish freaks? Although many people dislike this sort of game, essentially DMC is a "go and a get a key, killing stuff on the way, open the door, go find the next key, kill some more stuff" kinda game. I don't really have a problem with it. I don't see how free-roaming could be incorporated into a game like that and I wouldn't want it to be. (See also Max Payne, Abe's Odysee/Exodus, Most FPS campaigns and Prince of Persia Series)
Then the step up from that is games like Ratchet and Clank, Spyro the Dragon, Super Mario 64, etc. Where there is a clear path, but you do things in what order you like, within reason. In those sorts of games theres no sort of illusion that there is a final goal and you often have a good idea what that is. There is also a path you follow but you're often presented with something like 5 things you have to do and you do those 5 in whatever order you like, and so on. Theres also often optional things to do which aren't necessary to advance with the storyline, but completely them gives you a nice item (like all the extra stuff in R&C) or it is required for 100% completition (note how you can defeat the final boss in spyro without 100%).
Finally there are games which are still linear but because they include free-roaming people think they aren't. Examples which spring to mind are FFXII and Black and White. In both of these you can spend as much time as you like messing around doing whatever you want whether it be side-quests or just wandering aimlessly. It often pays to do both of these but eventually you'll get bored of wandering around like an idiot and get on with the story. Note that although both the above mentioned games let you do things in your own time, they both have a very clear storyline which can't be altered, no matter how much you spend wandering around like a lost drunk, eventually you have to get on with it, even if only to give you wandering pastures anew.
I would say the games which have provoked this anti-linearity are not much different from this. Although I haven't played the GTA series much from what I can see there is some sort of story to them, although the main appeal seems to be that you can wander around doing whatever the hell you like and blowing shit up, there are missions to be done, and eventually you'll have done all of them and the game will be complete, whether the game ends here or whether you're simply allowed to get back to the important business of blowing shit up I don't know. But the fact remains that even GTA has an element of linearity in it.
When it comes down it, every game is linear whether it be a clear story of just a final goal. Hell even AoE and Civilization are linear, eventually you want to wipe everyone out or wipe everyone but your allies out and then you've won. Without that the game has no purpose, and in that aspect it is indeed linear.