"Enough" is a slippery concept. Tautilogically, this is true, but it is equally true to say "The players haven't responded enough to the hooks presented", or "The players are not proactive enough", or "The players are not able to make decisions" and be equally accurate. Either way, the players are either not doing their job, or they're doing it wrong.
Except that it's a power relationship. No matter how much people argue otherwise and no matter how true the the GM has all the power at the table. Right up until the minute the players leave the table, that is. Since the GM has the power, it's his problem and responsibility to take the lead in fixing these issues. Maybe it's a communication thing, maybe the GM needs to adjust his play style. Everyone has a responsibility to make sure that fun is had by all at the table, but as first among equals the GM has the greatest part of that since he controls the horizontal and the vertical.
But both paragraphs -- yours and mine -- are equally meaningless for two reasons. First, what is "enough" is left undefined, so that one can always then say, "Ah, but if you had done enough things would be better." Secondly, both paragraphs somehow imagine that what happens during actual game play is controlled exclusively from one side of the screen.
Both are, essentially, attempts to cop out on responsibility.
Enough is implicitly defined in my comment. Enough hooks is enough for the players to find one that grabs them. Your argument that it's undefined is just trying to confuse the issue by playing semantic games with a phrase that is perfectly clear in context.
(I'm not going to quote and respond to all of your additional paraphrases of the same highly questionable point. Suffice it to say that I disagree with any gaming philosophy that places sole burden for the game's success on one individual, or that disenfranchises the ability of any individual to contribute meaningfully to the game.)
And I reject any gaming philosophy that dismisses the GM's responsibility to run their game and instead blames the players for every problem at the table, every mistake or misstep of the GM, or every weakness of the GM's preferred play style. One of the primary weaknesses of the 'pure' sandbox style is that it requires the players be completely self directing and self motivating. If they aren't the ball is in the GM's court. Either he needs to adjust his style or talk to the players about why they aren't. It's his (shared) responsibility to make sure everyone has fun. If some of the players aren't, it's his primary responsibility to address that issue.
As long as the GM has players who want to play his game, he is justified in running any game he wants. That defines "enough".
As long as a player is still welcome in a game, he is justified in running his character any way he wants. That defines "enough".
A wise GM doesn't wait until every player is gone before considering his game; a wise player doesn't wait until he is booted from every game before he considers his playing. That defines making a change before you fail to have "enough".
If Bob is GMing, and Marcy and Joe want a different game, Bob absolutely does not need to "step down"; he can keep running a game for Sue and John. If Marcy then runs a game more like what she and Joe want, perhaps Bob, Sue, and/or John will also want to play in that game.
If, for some reason, Sue and John can only play in one game, then either Bob's or Marcy's gets them, depending upon which is closer to what Sue and John want.
The only reason Bob should "step down" is because he is tired of GMing.
Nothing I said runs counter to that.
That you personally do not like sandbox games is immaterial.
You're right, it is. Especially since it's not true. I played in one for about a year until it folded due to the GM developing a case of parenthood, and I've played in another for the past... decade? I've lost count. I don't choose to run them because they do not scratch my GMing itch. You know what? I share players and with both those sandbox games without an issue.
What I dislike is the assertion that oh so scrupulously avoids calling the sandbox the one true way constantly beats the drum that they are a better, if not the best way to play.
Someone has an issue with a game with a narrative structure, "Run a sandbox and you won't have those problems." Someone asks for advice on running a mystery story arc, "You wouldn't have these problems if you ran a sand box." Someone has problems with their players not enjoying or playing in a sandbox, "Your players are are broken sheeple who you need to reeducate so then can appreciate the glorious sandbox that you are running."
The OP's players may be meat popsicles. He's tired everything with the possible exception of sitting down and talking with them about it. I say possible, because he didn't comment on that (or I missed it). They also may be bored and apathetic because they want more out of a GM then a keyed map, a monster manual, and a random encounter table. I don't know. If he hasn't talked with them about it, he's failing as a GM.
Sandboxes, despite peoples claims, are among the hardest medium for a GM to work in. They require the most preparation, the most player buy in, etc. That difficulty does not equate to superiority though.
So, if a player wants to do something, the GM slaps him down until the GM says its okay?
No. While the GM can do that, and the player's only real defense is to walk away, they shouldn't. By it's very nature, the player side of the screen can only effect change or take action if the GM allows it. The GM
should allow it pretty much as a matter of course, but it still only happens because the GM allows it. As I said above, the hand the rules least rules best and the GM is best served by viewing himself as first among equals rather then absolute tyrant.