Oh yes they would – and pay for it too! People already travel further and seeking weirder adventures IRL. Online ones would be an acceptable and cheaper alternative. Online socialising also increases.
Definately a viable business opportunity

Driving a car off a bridge, jumping out, and then harpooning another car below so you can paraglide behind it will never get old.

Anyone remember Privateer 2: The Darkening? That game was essentially identical to freelancer. Except with Clive Owen instead of John Rhys-Davies.

I am SO glad somebody mentioned Shadow of the Colossus. That has the most beautiful art and game world that I have seen to date.

Borderlands will be a must for you if you love open worlds.

You’re going to have to qualify that, because on the face of it it’s utterly flawed. You’re saying that gamers are not mature enough (in attitude?) for games to be made to appeal to them. This isn’t how it works. When a game gets made that appeals to a more mature audience, a small niche of more mature gamers will be brought into the fold. If this sort of game is successful and accepted, more games will follow directed at this audience. One way of looking at it is that there is already a group of more mature (in attitude) gamers out there, they just aren’t being catered for yet.

Aimless wandering is rarely an adequate substitute for a well-told story.

This clearly shows how close-minded you are that you think a game’s strongest possible point is its narrative. There are so many other elements made possible in games that aren’t possible in literature or film (social interaction on about a gazillion levels, open-world exploration, open-structure sandbox play, personal achievement via emergence and/or progression, personal and team strategy, player customisation, novel replayability, the list goes on…). Just because these aren’t what you classify as interesting, it certainly doesn’t make narrative the most valuable element in a game.

The most popular quotation in reference to games is Sid Meier’s “A [good] game is a series of interesting choices.” I would say that “aimless wandering” fails to be interesting if the player has no goal, just as a “well-told story” on its own fails to present the player with any choices. While either might make an entertaining experience to those that way inclined, neither on their own makes a good ‘game’.

The detail is what counts. But wide open worlds provide excellent photo op moments and that “Lewis and Clark” sense of charting vast, unexplored territory.

WoW has all sorts of little details that make the gameworld fun to explore. Ever notice how most MMORPGs feature dull expanses of rendered forests with little to explore in between?