How would the budget work for that? Could you reasonably project that the additional SP polishing would produce comparable revenue to what MP would bring in? And if that would be so, shouldn't they have done both?
Sure, it could and does. Again, I don't know Bioware's internal policies, but since they're not a Valve-type company, they operate within the same framework as and other AAA or medium sized studio. There's always going to be polish, quality control to a degree, it just depends on what you focus on. And, despite the enormous budget, like the game, it seems Bioware spread themselves too thin.
In the simplest terms, you could design the game as SP only, and aside from DLC, you could generate revenue by selling (in DA:I's case), different skins for companions (ME2/3 style), weapons/armor (although this would only really work if there was a lot more quality/variety in existing armor so the player didn't feel like they have to purchase to 'look good').
There aren't as many ways to monetize SP, but again, your initial product, by it's own merit should produce more than enough revenue to cover everything you need.
You mean walk out on Bio and start a new company? There's no real evidence that the staff has any problem with being part of EA; those who did are already gone. Bio's always wanted to play in the AAA space, even if a fraction of the fanbase likes to think of them as a niche publisher.
As for being a creative person, the old aphorism about Broadway is "there's a reason it's called show business." If you don't keep making money, you don't get to keep making games.
And none of this has much to do with whether Bio should have cut MP in order to polish the SP more.
You can ask around during conventions, or just research this, but you'll find out that most of those people who are already gone were the people that were the most creative, and helped build Bioware up to what it was when DA:O released. Hell, the people responsible for music/ambiance/sound have all revolved out.
A lot of indie developers would argue with your second point, the video game industry is nothing like the television/movie industry. The first thing you have to know when getting into games is you won't be making money, but still have all the tools and talent that any AAA studio has. In fact, that very term 'indie developer' is misleading because many of them, besides the designers, the animators, artists, sound devs, are all former-AAA people.
Do you know why the independent development is and has been rising? Because on an individual level, developers are sick of AAA. It's a source of pride to work somewhere like Bioware but that also comes with a massive bureaucracy, limits on creative expression, massive workloads, lack of communication, and generally from the publisher's side, a huge focus on marketing while the development team as a whole are treated like a factory, rather than the reason the marketing/publisher has anything to publish.
Go ahead, talk to someone who has been in the industry for at *least* 5-6 years, not a kid fresh out of school who's just glad to work there. They will universally tell you that there is a crash coming because the current AAA environment is unsustainable. One of the major problems is marketing and the publisher dictating what they think would sell well, having little to no experience that it would do so other than looking at other companies sales.
THQ was a giant publisher, and besides their myriad problems, one of the things they wanted to chase was what OTHER games were doing, rather than focus on their own strengths, what they were doing well.