That is, frankly, completely irrelevant when you're discussing a manufactured game. The manufactured game is what it is regardless what your table likes.
If you're using the term "manufactured game" how I understand it - D&D hasn't ever been a manufactured game.
If the game were written with strict rules, and run exactly as written, then yes, you'd be correct. If, in essence, the game was tic-tac-toe, and in an individual campaign, there were no choices for the GM in how he went about things, you'd be correct. An upshot of this is that the game experience would be unequivocal. Everyone would have the same experience of play. But that's clearly not what we see in practice. D&D is not tic-tac-toe, or even monopoly or chess, with single-style-results in play.
We can bring out the Gygax quotes of how the GM is allowed to ignore the rules, if you like. But even without that, and without blatant homebrew rules, the GM always has choices. The rules have always been littered with things that are optional, advice for the GM on how to *vary* the game to fit the needs of his or her players. The game has thus always been, to a significant extent, hand-tailored, rather than manufactured.
Does the GM go with a "wish list" for magic items, or does he drop them instead randomly, or by his own design. Does the GM use Skill Challenges, and if so, how often? How are adventures structured (because exactly how "encounter" and "daily" powers play out depends on how much time passes during a given adventure). Does the GM use masses of weaker monsters, or focus more on big boss monsters, or does he run an entirely human-centric campaign without "monsters" at all? Are XP handed out only for killing monsters, or does the GM reserve some for handing out for Role Play, or achieving success through methods other than combat - or does the GM eschew XP altogether! If the game has save-or-die effects, does the GM use them, or not? Is the GM using one of the 3e action point variants? Psionics?
These, and many, many more things, are all choices that can impact the feel of the game. Add in Rule 0 and outright homebrewing on top of that, and "manufactured" no longer really applies.
Your table probably already knows what it likes, what it wants to try, etc. That's a non-issue.
Even if you know what you want to try, doesn't mean you know how to try it. If someone has never before cooked pasta, they probably want to discuss what goes on in the kitchen before trying to make their own Italian cuisine.
The people who saw the innovation and modern game design strategy as a good thing in 4E don't want to effectively take a step backwards into a game which doesn't come as a completed product, which requires you to modify and tweak the rules in order to be functional in a meaningful way, and which allows for character power imbalance right from the get-go.
As noted above, even working within the rules, every table has already experienced this tweaking - the DM makes decisions, implicitly or explicitly, in how the game is run. Anyone who thinks they're going to get a version of D&D that is like Monopoly, with no choices in implementation, are expecting something rather extraordinary in the history of the game. In fact, so long as the GM has the handle on adventure choice and design, the "manufactured game" will never fully be achieved.
But, it can come close - it can (and always has) offered a basic set of defaults. This is how those who want as much "manufactured game" as they can get can play. But, if they then feel that their desires then preclude even the existence of options for others... well, I have to say they're being pretty darned selfish.