It isn't really plausible that Bloomberg made up the story. They had to have a high degree of confidence to publish it. The question we all need to be asking is why they had that high degree of confidence. Where their information came from and whether or not those sources had ulterior motives to lead Bloomberg astray.
I have to imagine Bloomberg is also trying to find out why their story has not matched statements by the companies alleged to be involved so starkly. There is a story here, but what that story actually is is definitely in question.
Yeah, my hunch (like yours) is that everyone involved--Bloomberg, Apple, AWS--believes, in good faith, in what they have stated, and have collected more than enough evidence to back those statements. Since there's a contradiction, the truth is probably fairly weird, if it's enough to provide so much conflicting evidence both ways.
The least weird conclusion is that Bloomberg connected too many dots the wrong way around and are embarrassed to admit it.
For a good example of how reporters can be mislead, or can mislead themselves by buying too heavily into a narrative, and not examining alternatives with enough scrutiny, read about the Killian Documents Controversy (about George W Bush's military service, reported by Dan Rather 60 Minutes); or read about "A Rape On Campus" (the Rolling Stone article that was retracted in its entirety):
In both cases, it seemed to me that the reporters involved crafted a story in their heads about what happened, and then only sought information that confirmed their story while ignoring information that contradicted it. The Duke Lacrosse case is an example of the same thing happening in a criminal prosecution:
Another theme that I've seen is experts giving an interview about some very specific/narrow topic, which is then spun, taken out of context, or generally misquoted by reporters and presented as something different. This happened with document verification in the Killian controversy, and also seems to have happened with this Bloomberg story, according to another comment in the thread: https://news.ycombinator.com/item?id=18278023 . In the Killian case, document examiners explicitly told CBS that they were relying on poor material that could not be authenticated (see Wikipedia section "Response of the document examiners"), but CBS went ahead and characterized the documents as having been authenticated by experts.
I totally agree, I think they cobbled together bits and pieces and kind of put it together based on what they could find. The one guy they interviewed who is willing to talk said explicitly that this is what happened to him: https://9to5mac.com/2018/10/09/bloomberg/
It's not clear how much oversight Bloomberg has over the detailed process that the journalists used to get their information, aside from what they presented to Bloomberg. Based on accounts from some people they talked to, it sounds like the journalists involved are conspiracy-types who will take any bit of speculative information and run with it.
I have to imagine Bloomberg is also trying to find out why their story has not matched statements by the companies alleged to be involved so starkly. There is a story here, but what that story actually is is definitely in question.