You're quoting the phrase "seems likely". It's not a conclusion. It's my guess at what's most probable based on what we know today.

(Also, I don't agree that we only know "wild speculation" about the Lion Air crash. The investigators have told us much about the proximate cause of the crash, even though their final investigation is not yet complete.)

Maybe it’s my English. What probability do you assign to “seems likely”? Above 50% (the way I read it)? Or does it mean it’s a possible outcome among many others, all with very low probability?

I would read it the same way, but personally I would want to attach an additional qualifier: It's likely that this is one of the causes.

There may or may not be something inherently problematic about the way the MCAS works, but more thorough training would likely have lowered the chance of these accidents happening - having the same type rating was one of the root causes for the lacking training

Flip that around: would you expect that pilots flying a new aeroplane without any conversion training would be more likely to cause an accident.

It's a damning indictment of Boeing, and whichever authorities let them get away with it, that they pushed through an aircraft with a different pilot UI/UX knowing that pilots would then be under trained when using it: like someone said we train baristas better.

I've driven minibuses before and always ensure to get an hour of driving a new model before taking passengers.

At least in this particular instance... how is it Boeing and aviation authority's faults that pilots are given an hour's notification they'll be flying a new model of plane?

That would seem to fall directly on the operator / carrier.

Boeing takes responsibility if the training manuals were not comprehensive. Aviation authorities take responsibility if they under-mandated training. But ultimately neither know a given carrier's scheduling and pilot allocation.

I assume an hours notice is quite typical for pilots to find out which specific airplane they will be flying.

If the carrier was told by Boeing and the FAA that no additional training was needed, why would they use any different procedure.

Because their pilots had previously told them they didn't feel comfortable? (See report)

At some point this falls back on nannyism. Either you have a functional company, where your employees are empowered to communicate internally, and your company does something about it... or you don't.

Boeing's job is to engineer the billion things required to keep an airplane flying. The government's job is to validate Boeing performed due diligence and mandate what training is required to the carriers. The carriers have a job too.

I wouldn't be surprised if Boeing pushed hard to have it same type certified. Why wouldn't they? Ultimately, regulatory agencies agreed. Maybe that was correct, maybe not.

But absolving the pilots' direct parent company of responsibility is bullshit. Aerospace is a different industry, but it's not that different vis what a healthy, functioning company does.