The production troubles articles echoes some stuff I heard and it does make sense. I don't really feel there's any one individual that can be blamed, as it's a multitude of failures, but many of those failures could and should have been squished early on.
And I'm not convinced longer production would have fixed it. When your underlining issues are management, planning, and technical competency, simply adding more time and manpower is not a solution. You might get a better end result, but likely still one plagued with issues.
Andromeda's faults seemingly were due to a lot of time frankly wasted in pre-production, having a vision and building tools which never came to fruition and set the production phase of the project back. When you enter production phase without your vision set in stone, and without a solid vertical slice, and broken and incomplete tools, you've set up a recipe for disaster that's already in the oven by the time people realise the mixture is wrong.
Cancelling DLC is the logical step to squishing the franchise. Obviously never say never, but based on grapevine I'd say Mass Effect is most definitely "on ice" as per rumours which in EA language means fundamentally dead. Licensed, but dead. By the time they might try to revive it there will be other scifis filling the gaps (because I figure it'll be that long), and at best we'll get a remaster port late generation.
With Andromeda it was EA seeing if they could continue this franchise into a new generation. Montreal seemed to feel the same way; a restart for the franchise. Mixed critical and commercial reception sends a message that this investment isn't worthwhile, for a number of reasons, and money spent on Mass Effect's future could be better spent elsewhere.