So I'm guessing this is still a relevant theory, then; They planned it from the beginning!
From what I've seen, this is the truth. From a certain point of view.
...no, I don't think they did. But deliberately fucking up everything about the end they could fuck up, then getting you a payable DLC to fix it?
I don't think it was deliberately fucking up from their point of view. With a little bit more exposition, the endings could be bloody magnificent. The scene with Anderson and Shepard, absolutely awesome. I actually wish they'd ended things there instead of extending it out with "Starchild". They could have even left it with a cliffhanger, and I'd be more satisfied. "Shepard... Shepard are you there? Nothing's happening, something went wrong with the Crucible..." /fadetoblack
That would be a very bad plan. I still want to hear the official excuse for exactly why the game was brilliant but the ending flopped about as badly as it possibly could flop. Was it EA's decision? Was it a Bioware manager/programmer/employee/asshole who decided? Did they run out of time? Did they plan this face-slap from ME1, or what? I'd like to not have several ideas and several indicators for all those ideas to possibly be valid. I'd like the straight answer and a single location to place the blame and the request that they kindly take responsibility and fix what they broke.
As they say, "no publicity is bad publicity".
They hyped the heck out of ME3, and it's still being "hyped". They got their launch numbers, their preorder numbers, and they're probably getting a lot of positive feedback from multiplayer (on PC requiring Origin no less, so EA is probably VERY happy).
The assumption here is that a loud, unhappy player base is a bad thing. If the money is still coming in somehow (Multiplayer requisition packs, for instance...), and there's people buying the game "just to see the bad ending", then the fact that this is the
last game in the trilogy pretty much guarantees that they won't have to worry about bad blood hurting their next successful franchise.
I could go into the whole marketing/demographics reasoning behind this, but I think I'll end here. Point being, this isn't a niche game like EVE where alienating the core audience is going to sink the company. Bioware is diversified enough, and EA is giving them enough backing, that they will probably survive this PR hiccup.
Namely, customer trust in their brand-name and the idea you actually get what you pay for. ME3 player's didn't.
That... is the only potential problem. If
this idea is the one that survives all this, then yeah... ME3 could be an end to trust in future products from Bioware. But it's just a "potential" problem. As it stands, they have SWTOR still going strong (presumably), VERY successful ME3 multiplayer (probably making them a bit of cash from "whales" maxing out their arsenal and character selection), and the experience to move beyond RPG games into more mainstream shooter/pvp/f2p MMO territory. They even have some experience now with social games (Dragon Age Legends, and ME Datapad/Infiltrator apps).
And about the multiplayer side of ME3... unlike one-time DLC, multiplayer DLC "Lottery Packs" can be purchased multiple times by the same customer. So, yeah. More cost effective to make a multiplayer expansion (with new races and weapons, unlockable by either grinding away at the multiplayer or paying money to get a chance of unlocking what you want) than resource-intensive and one-time-purchase DLC storyline content for the single player game.
So... would it be "stupid" to make a bad ending for a game, and then later "enhance" that ending? NO, not if the expanded content was already written/voices already recorded. "Cut" content is more cost effective than "new" content. If they already thought the ending was "brilliant and artistic", why would they worry about customer response?
If they didn't know it was bad, and had blinders on in regards to fan interest because "the die-hard fans aren't the ones we're marketing this to" (see the Battlefield 3 early access promotion), then it makes much more sense.
It may not be 100% "ethical", but it's 100% in line with making money and ensuring that you can get the most bang for your development resource buck.