Because that is the what the very demographics have shown. Fanatics (you notice the root word is "fan") will stick by anything they believe in no matter what about it they do not like. This is why you get whole gamuts of different Christian religions all based on the same book for example, or the numerous Star Wars fans who refuse to accept that the Prequels ever happened. The sheer fact that the "deep lore" itself exists shows they are catering to you, its just they know that you won't leave, or in any significant numbers at any rate, whenever they do their nips and tucks to tell the story they want to tell. This rather clearly tells me that it is not actually important no matter how much you want it to be.

Not necessarily... I suspect you're probably underrating the importance of lore; A: because it's being referred to as "lore" rather than as "continuity" and B: because it's in a fantasy context, and therefore easy to discount as a form of "wankiness"... see "A". The fact is, if we were talking about "Gears of War", "Tomb Raider" or perhaps "A.C." it would be understood that any discontinuity with previous installments would be an instance of the game being poorly written. Lara Croft cannot appear in future games as a self-made daughter of welsh coal-miners, it'd annoy folk. Hell, how well would dikeens' serialized novels have sold if, from one installment to the next, he randomly changed the history of his characters or the setting to suit the fashion of the moment. Games are a fiction like any other, and not retaining some consistency ain't a smart move... it's laziness, not smart marketing, and certainly not a recipe for a memorable and long-lived fiction.

Sure, which is why the numerous remakes and reimaginings of Shakespear's plays are all seen as annoying and poorly written? How many different settings have they been translated into?

Nah... different issue... personally quite enjoyed, say, the version of 'Richard III" set in the 1930's it was a good thing in itself; however if Shakespeare himself had between "Henry IV" part one, and "Henry IV" part two dropped Falstaff and, I dunno, decided to remove the war from France to perhaps Turkey, as an Elizabethan fan (or indeed any fan) I would've been chucking rotten vegetables at the stage. Likesaid, an enjoyable fiction requires continuity... games are no different.

Not really. The point is that backdrop is only important for the parts of the story it directly affects. The Clone Wars cartoon blatently breaks the Star Wars lore yet is super popular. Anything that gets rewritten at the drop of a hat in order to make a better story just cannot be super important.

"Super-popular"?... if you say so... however, in that regard, 'Star Wars' is a good example: Can't say I've ever given a faff for the series, but when you compare the weight the series carried in the 80's, before they started effing about with it (I can remember, as a twelve-year-old, having arguments about the accuracy of various figurines, and their relative importance) compared to it's standing today, the decline is startling. Incidentally, for the first three movies, Lucas had 'script-editors' he would defer to; whereas for the second three, having decided he was a genius, he simply pulled stuff out his [censored], and would brook no nay-saying.

The fact is, creating a persistent world is what makes the difference between a "Henry IV", a "Tale of Two Cities" or even a "Star Wars" versus a "Clone Wars"... you're right, [censored] that can be re-written at the drop of a hat, in the long run, ain't worth [censored].

The problem being you would be hard pressed to argue that it actually DID carry more weight in the 80s. Look at volunteer groups like the 501st for example. And that is far from the first time that major rewrites of lore have been done for Star Wars. Look at the comics and really half of the expanded universe.

Assuming you are being facetious, the problem with this statement is this applies to all franchises eventually. The larger they become the sooner it happens.

Which typically is not a good thing.